heh, its strange, but mine old settings "-l F1536x16 -L 256" still give me 2-3 MHash more than the advised "-l F384x16 -L 512" : 39MHash (old) vs 36-37 (new) ?
GTX550Ti 1Gb VRAM (192 cores), last cudaminer build from 09.02, WinXP 32bit
p.s. Maxcoin it is, stratum pool
maybe for low shader count cards higher multiples (4x, 6x, 8x) are even better.