If you are running 8.1 on that Quadra, 192 megs would be nice.

Regardless of what you do, I'd definately hold on to those SIMMs. 30-pin SIMMS are only going to be more and more of a pain in the ass to find. Especially in the larger capacities. By the time the first Pentiums and PPCs cams out, the industry had switched over en-masse to 72-pin SIMMs.