Got my 7000 yesterday, and had to do a rush job to prepare it for a gig last night. (Took some floppies, just in case)
Saved 40 x 3 Bank files, which included Composer & Sound Memory, and 6 x All files which also included Composer & Sound Memory.
The result being I'd used 49% of the 8Mb SD card, leaving 3,352Kb free.
The only test I managed to find time to do, was to load one or two files, then save them again excluding Sound Memory. That's when my brain started hurting
Sometimes there was a little more free space, but sometimes less!!! Needless to say, I've ordered a 128Mb SD card. I'm off to Warwick with the caravan in the morning. I've offered to leave my wife there whilst I come back home to work on the 7000 or alternatively take it with me. She wasn't very impressed with either idea.