Faster RAM will do nothing unless the memory controller can use it, if Apple said use 80NS RAM then anything faster will not speed anything up.

If you are going to use OS 6.0x then 8x1MB would be perfect. 1MB SIMMs are dirt cheap (you do not need parity). 4MB x 8 = 32MB and great for OS 7, not too expensive. 16MB SIMMs are pricey and unless you have a 68030/50 or 68040 upgrade a waste of money and time. One of my S/30's came with 128MB and I replaced it with 32MB.