Any thoughts on a solid hickory platform under my tt

I think there is absolutely no way to predict the end result without trying it.  Some tables, especially the Linn, are tremendously affected by what they sit on and others are not.  Plus, it's not about damping per-se.  It's about what your ears prefer.  That's why some people prefer not to use record clamps - they feel the sound is too dead without the little bit of resonance created by an unclamped record.  IMO, worry less about damping and more about what sounds good to your ears.  Good luck. 

Just FYI, I ended up with a Corian platform on my wall shelf when I had the Linn.  It sounded significantly better to my ears than glass or wood.  I left it there when I bought my Basis and never bothered to try anything else with it.  But don't overlook Corian, is my point.