I compressed Bust a Move 3000 to 31,1MB only, maintaining the original 1.392MB GCM, since i don't want to shrink it right now (gonna wait until next releases).
At the moment, for testing, i just used 7-Zip to to compress to .7z format.
Seems to take a while compressing (around 5-10 min. on my computer), but when i just want to test the emu, i just uncompress it to full size.
I know it isn't much compared to the other methods, but it's a nice try and seems to saves a lot of space.
Also tested Bust a Move 3000, but everyone now knows that it works after shrinking.
Keep the good work.