Getting my head around editing in h.264, Proxy Media, or Optimized Media for Canon DSLR

Question

I'm trying to understand these different workflows, how they work, plusses and minues of each, with a focus on how it relates to file size.  Please help me fill in the gaps
Here's what I think I know now.
Optmize meda to ProRes 422
Better for performance, but creates HUGE files.  On 30 GB worth of h.264 footage, the optimzed files were over 100 GB, not including any render files, etc.  I'm running off a laptop and only use external drives for storage, so I'd like to find a better way that uses less disk space and requires less time to convert (took all night for those 100 GB)
Proxy Media
Creates an easy to edit file that is very poor resolution and quality.  You can use this for editing, then before final export, switch back to original/optimized media and it will re-render and reconnect with the good media.
QUESTION: If I ONLY do the Proxy optimization, do I need to also Optimize to ProRes 422 at some point also, or can I just have it refer to the h.264 .mov files and get equivalent results?  If I can, this seems like a good compromize.
Editing directly with the h.264 footage
I have read that some people are dropping the footage directly into the timeline and editing without any real problems.  Others say it will cause performance issues and to always optimize.  Ideally I'd like to do this way as it is the quickest (no conversion) and has the smallest file sizes of all of them.
It would also be useful to start out this way and optimize later if I need to on the smaller sub-set of the footage.  But I have found no good way to do a rough cut with little editing and then select only those clips used in the timeline for optimization in case I start experiencing slowdowns.  Yes, you can clip-by-clip select them and "show in event browser," but you can't do this with multiple clips as far as I can tell.
So what are your workflow tips for keeping file size down?  What am I missing in my understanding of these options?
I'm on a 2010 MBP i7 (dual core) with a 7200 RPM drive for what it's worth since I know the h.264 one largely depends on the hardware.

Answer 1

Proxy Media
If I ONLY do the Proxy optimization, do I need to also Optimize to ProRes 422 at some point also ...
Nope. You don't need to do the "Optimze Media" at all, you can use with the Proxy media for your working edit, then switch the references back to the Original media for mastering/export.
... or can I just have it refer to the h.264 .mov files and get equivalent results?  If I can, this seems like a good compromize.
Exactly. And yes it is, an excellent compromise. Start working with the original media right away, but have FCPX create proxies in the background (which it switches to using as soon as each one becomes ready); if at any point you need to check a clip in place in the timeline in full resolution then you can just quickly toggle your general playback preference to "Use original", otherwise just edit away with the proxies and then switch that preference back to "Use original" when you are ready to output.
Editing directly with the h.264 footage
I have read that some people are dropping the footage directly into the timeline and editing without any real problems.  Others say it will cause performance issues and to always optimize.
Yep, you can edit just with the original media if you choose but your source footage is H264, a dreadful edit codec by any measure, and certainly you will get much better timeline performance if you work with transcoded Optimized or Proxy media instead.