I've tried with and without clamping using a VPI clamp on my 1200GR and can't tell the difference. For this reason I say no clamp. BUT, I also use a Herbies mat that could offset the sonics of the stock rubber mat if used with clamp, which combination I have not yet tried.
Technics 1200G - clamp record weight or no record weight?
It seems as though 95% of the time the 1200G sounds better without a clamp or weight. I use a Boston audio mat and it seems when I add a clamp or weight, it may sound pleasing in some ways for some records but most of the time records seem to sound better without anything... maybe its just the mat does not like the clamp. not sure... How are your experiences? So far I have used the Project puck, Stillpoints LPI, Orsonic 200 gram clamp. The Stillpoints may sound the best in some circumstances but it seems that the lighter Orsonic works pretty good.