High or low-mass record weights/clamps: which is best?

Oracle themselves have been through quite a number of mat systems over the years - sonically very different solutions too.

really meant with a oracle you can,t play records without using the screwed record clamp , part of the design , very good with warped records
used the supplied mat with the delphi , had it for 30years now design classic
Also used a acoustic signature this used a huge screw clamp as well

Hmm... I'm not a fan of the concave platter approach.

Why is that, Mark? Out of pure interest.

bought a oracle when they came out , still have it after 30years
never missed a beat since the 80s , only the led on the front failed
delphi Mk1 , sumiko MDC800 the arm , EMT tsd
always found the concave mat & clamp worked great
Still always gets the same response
" Thats lovely what the fuck is it "

I have always love the Thorens stabilizer and used one for 8 years.

I've recently added an Oyaide MJ-12 TT mat & was resigned to having to replace my Standard spec Michell clamp for my Gyro s.e.

This was due to the now shortened exposed spindle length caused by adding the Oyaide. I've found a neat fix though for any facing a similar situation. If you add a suitably sized O' ring to the clamps underside & pass the central locking "Pawl" thingummybob through it it'll cope nicely with a shortened spindle as it "Pre Loads" the locking element of the clamp & it's already biting nicely as you slip it onto the spindle'

I'm actually finding that as a clamping arrangement it is now working far more nicely than it ever did in standard trim with just the Gyro platter. I've also found with a couple of Albums with fairly severe warps that these have effectively been ironed out. I never got close to this with the straight platter despite much experimentation with foam rings & various placement options using the supplied felt washer.