here's my theory:
when creating swap files on memory cards, I would recommend the larger the swap file the better!
you want to spread the wear on the memory card as much as possible, if you force the kernel to use the smallest swap file possible, it will be writing the same set of memory cells intensely (assuming that the card can't somehow write new data to a completely different region of flash), but if you make the swap file really huge, it will not need to use the same area twice?
how about swapping over the network? on a previous project, LinuxAP, using a eumitcom (x86-compatible) system, it was possible to swap over the network block device, which could make a big difference to performance (it only had 4MB of ram).
Paul