All points taken, fellers!
I really am listening to everyone, though at this point I have so many voices in my ear it's easy to become derailed. I have no idea how to figure out the resonant frequency of my turntable, stand or base.
So at this point what I'm doing is just having some fun experimenting and ultimately I'm going to go with the method that gives me some peace of mind. It's not of course that I think I've solved any vibration issues scientifically. I think it's more about the mind-set my experiments create. Just being able to distinctly feel the differences various material make in vibration gives me a more tactile basis on which way to go. Among the many different suggestions I've received, and all the many other threads i've read, no doubt there is more accurate info, but it's hard to discern which it is. So, again, I have to ultimately go on what makes me happy. I doubt anything I'll be doing will actually make an audible difference (I admit I'm pretty skeptical about the tweakier side of high end audio), but I enjoy the idea of making a design based on my own ideas playing around with various materials/devices.