Can I remove a specific dated backup from time Capsule?

Question

Sorry for the long story - but I have tried to provide as much detail as possible as to what is going on...
Sadly Lion has been a royal pain in the perverbial for me. It is slow (on a Macbook pro that is still within its warranty period so I don't believe that Hardware can be blamed - especially with upgraded ram and a 7200rpm drive) I recently got so frustrated with its clunkyness that I tried reinstalling on a new HDD and booting off that. Showed improvement (clean install vs upgraded and less apps etc slowing down the OS - however it is nowhere near what Snow Leopard was). But while I was at it I did something stupid. In hindsight very stupid - but balls to Apple for putting me in this situation and balls to Apple for letting me do it with no warning about the consequences...
I connected my old HDD via firewire and tried to access my files that are on it - I couldn't initially as my newly installed user did not have permission. Easy - Add the new user to permissions for folder concerned - apply to enclosed - done - Achieved what I wanted. Files accessed - test complete - sadly I will have to reinstall a clean lion and transfer my files over (restore from time capsule).
Two Major problems have surfaced. The first is directly related to the topic, the second I might try to repost in an appropriate section...
1) What I didn't think about is as soon as I modified the permissions Time Capsule treats all the files in that folder as being modified. So it has backed up an entire new version of every file in that folder - a few hundred GB. That has chomped out 10-20% of my Time Capsule. I have no need for these backups and want to delete - say - every back up made since last Sunday when I committed the dirty deed. Seems minor - but this is a major compromise to my current arrangement.
2) I have MAJOR permissions issues now. Firstly my Aperture library (which was in the folder with added user in the permissions) is fried. Can't be repaired/rebuild or anything. Lion wont do anything so useful as to tell me why - just get the colourwheel of death and the aperture library NEVER opens. Balls to Apple for allowing this to happen so easily. Second I tried to restore the entire pictures folder from Time Machine. It tells me I don't have permission??? WHAT. Double Balls. These are my freakin files - created by this user on this MBP on this install of Lion. I can't see how adding a user can suddenly prevent a long standing user from accessing their files from within their account. By the way the new install on the new HDD is no longer in play - all I am trying to do is continue to use my MBP the way I was before I did the test install.
My long running affinity for Mac is rapidly waning - I have wasted countless hours trying to regain access to ALL of my pictures - 14 years worth. 1000's of images. I cannot access them on my MBP, Can't restore them from Time Machine. This is the worst computing experience of my life.
I have tried booting from recovery, repairing permissions etc etc etc. Nothing mainstream solves this.
Does anyone have some wisdom to address my conundrum - I am seriously desperate here... I have genuinely decided that I will not waste the upcoming long weekend ******* around with this - I would rather forget my 14 years of stored memories and just get on with life... If unsolved by this Friday I will sell my Macbook Pro and iPad and initiate my own version of the post PC world - no computer at all - currently it is doing nothing but wasting my time.

Answer 1

jameski wrote:
My only concern about resetting premissions (and ACL???) is that it will exacerbate my backup disk space wastage issue as it will result in full backup of my entire home folder (about 400GB).
Yup, if you changed the permissions on everything in your home folder, that will change them all back, so they'll all be backed-up again. 
That will leave me with about 1.2TB of a 2TB TC used up with backups (currently should be about 500GB) - my plan was to have about 1.5TB of my TC available to use for files in the medium term until the need for more backup space pushed me to invest in another drive. TC's are just too expensive to waste like this.
Mixing backups and other data on the TC's internal HD will, eventually, cause conflicts.  But see #Q3 in Using Time Machine with a Time Capsule for some possible workarounds.
If I do a complete restore from TM (entire account)
You can't do that.   You can't restore an entire home folder via the "Star Wars" display, because the home folder and default sub-folders (Desktop, Downloads, Pictures, etc.,) are protected.  You'd have to restore the contents of the sub-folders, a rather tedious process. 
You can do a "full system restore" (OSX, apps, all user accounts & home folders), via a different procedure (Time Machine - Frequently Asked Question #14).
to the day before this shambles started - will time machine treat my restored account as a modification of all files and try to back up a fresh copy of everything on the basis that it has been modified - or is it smart enought to realise what I have done and carry on doing only incremental backups?
Anything you restore via the "Star Wars" display is considered as changed, so will be backed-up.
A full system restore (usually) results in only an incremental backup, but TM does a "deep scan" to compare everything on your system to the backups, to see what's different.  That will find that everything in your home folder has changed, so back it all up anyway.
If yes I will likely put all my historical backups onto a cheap 500GB drive and put it in a drawer and start new backups on TC
Good plan.   You probably know you can always view and restore from those, via the Browse Other Backup Disks option, per #17 in the FAQ.
After you do that, in theory, you could run the user home folder permissions reset, delete all the backups made after the original permissions change, then force a "deep scan" so the only differences found would be files that really are new or changed; but that's tedious, error-prone, and "iffy."
Are backups via TC inherently substantially slower than say to firewire drive?
Oh, yes, absolutely.  Here's a very rough comparison of full backup speeds (see #29 in the FAQ for details):
There's a lot of variation depending on your hardware and setup, of course.
I am running my TC through gigabit ethernet as wifi (despite having an ethernet extended AEP in my office) is too slow. I simply cannot get over the serious loss of performance since Lion and more recently the introduction of a TC. It is dire!
Some folks report WIFI backups slower under Lion vs. Snow Leopard, some think it's faster, others (including me) don't see much difference. 
However, it really shouldn't make a whole lot of difference for normal incremental backups, as they should be relatively small and quick in most cases, and shouldn't have much impact on performance.  You might want to check the sizes of your backups -- if they seem too large considering what you've changed, see #D4 in Time Machine - Troubleshooting.  If the sizes are reasonable, but the backups are still slow, or other performance seems to suffer, see #D2 there.
Are these your only backups?  If so, consider keeping "secondary" backups, to avoid having "all eggs in one basket."  See #27 in the FAQ for some suggestions.