Want to remove Lossless files from dual-format library, keep elsewhere

Question

My iTunes library consists entirely of music ripped from audio CDs. Each CD was ripped twice, once in Apple Lossless format, once in AAC format.
For several reasons (chief among them the desire to free up a lot of disk space on my iMac), I want to remove the Lossless files from my iTunes library. But I want to keep all of the AAC files there as they are, along with my playlists (all based on the AAC files only).
However, for a measure of future-proofing, I still want to keep the Lossless files. And whenever I buy a CD, I want to still import it as both Lossless and AAC, keeping the Lossless files handy while adding the AAC files to the iTunes library.
I must obviously begin with an external Firewire drive big enough for my Lossless content. How do I proceeed from there?

Answer 1

I would take this approach, but others might have better suggestions.
First, when you get your external drive, copy the entire iTunes folder to the external drive which will copy everything (media files, database files, artwork, etc.).
Assuming you use the iTunes default settings where iTunes copied added items to your iTunes folder and organizes your library (meaning - everything is all self contained in the iTunes folder), then all you have to do is drag & drop your iTunes folder (not just the iTunes Music folder you find inside the iTunes folder) to the external drive and copy the entire thing.
If you want to test that it worked or would like to actually start using it from that location instead, use these instructions when you start iTunes to point it to the new location...
How to open an alternate iTunes Library file or create a new one
http://docs.info.apple.com/article.html?artnum=304447
If you are just testing, then close iTunes after you verify it works, and restart iTunes again with the same instructions and point it back to your internal drive (original) location. Now you can sort your library by "Kind" which is the format it is encoded as and all the Apple Lossless files will be grouped together. Select the first one, scroll down to the last one, Shift-Select the last one which will select all the ones in between and hit delete! Now your internal drive library is everything except Apple Lossless.
If you wish, you can switch back to the external drive library and do the same for the AAC files.
Now when ever you add a new CD you can do it a couple ways. But probably the most straight forward is to simply put in the CD, open the internal library, import as AAC files. Switch to the external library and import again as lossless.
Patrick