To answer some of your questions...
No I don't use the usb transfer, just midi in/out from midiman midisport 1x1 on a windows 7 laptop.
I'm leaning towards full memory
I think I'll find an empty pattern and copy/overwrite that to some user patterns I don't like, compact data again and see where it goes from there regarding the p2500 patterns. I'll let you know if this works for future reference
Thanks again Steve.