Nice post.

A bit late to this party but one of the tweaks that has stayed on my 401 was a SDS platter mat topped with a rubber mat froma Dual 505. I bought my SDS mat when they cost around £50 but it looks like they are double that now, if I see correctly. The dual 505 mat may seem a bit of an oddity but I found that this contributes no static. When I had a felt mat dust would dive on to the record like kamikaze pilots.