@wturkey , Yes, the platter has to have a reasonable gyroscopic effect to smooth out speed imperfections. Even DD tables are using heavier platters now. However there is such a thing as too heavy for standard bearing arrangements because the heavier the platter the faster is bearing wear. Exceptions are tables with magnetic thrust bearings and air bearing thrust mechanisms. Very heavy platters create other problems. Because they are harder to accelerate and stop belt wear is faster. If they are not perfectly balanced and leveled they will wear out the bearing sleeve. Only the Kuzma air bearing table would be immune to this and indeed Frank almost doubles the mass of the platter. He still does not have vacuum clamping. He is obviously convinced that reflex clamping is good enough.
At any rate. I personally think anything over 20 lb is a waste. There are many turntables with lighter platters that have SOTA speed specs. The Sota turntable is special because it corrects speed deviations slowly so you do not hear it happening and the speed will remain stable to 0.003 rpm. Sota is so brazen that the Condor displays speed in real time down to 0.001 rpm. At this moment it is reading 33.335 rpm. The platter weights 20 lb I think.