To add: for performance reasons, I tend to recommend against turning off virtual memory in any PowerPC-based Mac. Helpfully, I've never actually sat down and tested it, so if the general concensus is either (and, I've forgotten the technical reason) that the SSD's speed and random r/w performance negates the problems with turning off virtual memory, then it's a fine option.
The other option is to just have enough memory not to hit virtual memory option, since if I remember correctly in 7/8/9 it won't hit virtual memory until you actually fill main memory. Another option, of course, is to just buy a new and good enough card to be able to avoid this problem.
Anything old enough for CF to be a very reasonable choice on, you won't need a 256gb card. The sweet spot is probably 32GB cards which you can use fully
in at least 7.6.1 or newer on supported machines. If you've got anything older than that then you'll either have to deal with many partitions or you'll want an older card.
Given the cheap nature of SD cards, that's less of an issue (and, sizes like 8GB are still readily available, at least in the US, often for under $10 for good brands at retail, meaning you can walk over to your nearest gas station or grocery store and buy another SD card for your scsi2sd) - and there's of course no
moral problem with just not usng some capacity. I'm currently using just 256 megs of a 30-gig card in my Apple IIgs.
I have been meaning to, but have yet to actually, test SCSI2SD v5, v6 and a SATA card against the stock hard disk in my Power Macintosh G3@300. Unfortunately, due to upcoming travel and the fact that I've had this intention for the better part of a year, it'll be "A While" before this actually happens.