The red machines were initially designed as sketch pads for writing songs and getting ideas down, hence the smaller cards that came with the recorder. And they don't give much actual recording time before using up the space on the card. I never used anything larger than a 512MB card when I had the red machine, but I was transferring my tracks to pc and doing the mixing /editing in a DAW. Seems to be the way to get the most out that recorder.
I found an MR8HD in the shop of the guy that works on my guitars, he sold me for $80. Substantially more recording time and still imported to PC for mixing and editing. Back then there were still issues of latency with direct pc recording and this was a way around it. What I like about this method was keeping tracks in folders, so if a flub or erasure occurred, you still have the original takes in the folders. Easy and seamless punch ins as well. I bought an A/B switch pedal at Radio Shack and it works like a charm.