instead of decreasing filesize, try increasing space...
assuming you use gecko:
in the pf directory create:
dummy1.dat
dummy2.dat
border.dat
all 3 files must have 1 byte of '00' before being read
(this will allow them to replace the disc files, otherwise gecko ignores them (or so this seems))
this is still not fully tested, but it appears to work for me...
The thing is this is being done for a PSA, I haven't used USB Gecko before either. Right now I am focusing on making animations, So I need to lower the filesize at much as possible.
Link's FitMotion doesn't even exceed 2,500KBs, so I don't know why the filesize rose so high, even with the amount of Keyframes I deleted.