According to Rega’s lead engineer, nothing should be put on top of the platter as a clamp or weight is not part of the design. If it were, they would include one or make available as an optional upgrade like they do with a shelf, improved belts for their lower end tables, etc.
I am sure it is incorporated into heavier table designs like SOTA, VPI, Oracle, Clear Audio, Basis, Michell and the other big boys who sell or include weights/clamps along with their tables.
As far as @drbond ‘s original question, IMHO I would go with an integrated arm/table design like SME. You know it was designed to work together, and SME’s arms supposedly are outstanding and now only available new from them when buying one of their tables. I view SME as an end game table, maybe you can work your way up to their top of the line.