Hi Ken,
A most impressive design and I am sure that the execution will be first class as well. I look forward to hearing your thoughts on the final product along with analyses of the strengths, weaknesses and/or differences between your various tonearms and cartridges. May I ask how you built or sourced the vacuum platter? It looks quite similar to the platter on my Basis 2800 vacuum turntable. Very nice indeed.
Enjoy that extensive vinyl collection,
Aaron