First off, if you wanna try new things, play older games you haven't played before like psx, snes and genesis games. When games started to not work with 3.55 and multiman allowed psx backups to play easily, i started going crazy with the imports and backups i had. A lot of my psx games are so scratched up, it was heaven to finally play them again. Great games last the length of time. I'd rather play older ones that are still raved about and recommended than seed through newer ones that no one has played yet and learn that they suck.
I can sort of answer your questions since we pretty much seem to have the same amount of knowledge. You can have 4 partitions, i think it is 45 gigs each on an external drive to load back ups of newer games. Each partition is just one game, because it bd-mirrors that partition and makes it look like a single drive.
The debug eboots, i'm not so sure about. People seem to be getting them pretty easily, so maybe multiman can find them, or you just patch them on your computer, which again, seems to be pretty easy the way people are talking.
If you have the disc, you can just pop it in and play if the firmware you have on your ps3 is high enough.
It seems like getting to a developer firmware is the hardest part, then the rest is just lather, rinse and repeat (easy).
Never there but always going back