Screw-down reflex clamps vs. record weights

Thanks for all the contributions so far.
I have to specific points which may help to concentrate the discussion.
When you replace a screw-down reflex clamp with a record weight, you are giving up a clamping system that specifically seeks to take advantage of the two obvious ‘evacuation routes’ for vinyl resonances, through the platter surface and through the spindle/main bearing.
Record weights do little to bond the record to the platter, so they presumably are not in the business of optimising resonance-damping through this interface. On the other hand, the platter is still there and the record is still in contact with it to some degree. So it is in contact with whatever mat you have on the platter or whatever surface the manufacturer chose to give it - Isodamp in the case of an SME platter. Does the nature of this material make any difference to the functioning of a record weight like the Kuzma Ebony? I don’t know what material is on the top of the Kuzma XL platter, but presumably this must be compatible.
What about the spindle/main bearing evacuation route? All clamps and weights have some contact with the spindle, and thus potentially could make use of this to evacuate resonances. Is the Kuzma Ebony - or any other record weight, exotic wood or otherwise - designed to optimise this channel or is it instead designed to minimise contact there, so as to favour absorption of resonances by the weight itself?
Grateful for any reflections on these points.
Thanks,
Peter

Thanks, Dover, for the “complete lack of understanding of clamps/weights”.
If you reread the sentence that you quote in its context, you will realise that I am making a distinction between ‘clamps’ (= devices that grip the spindle either by screwing down onto it or by holding it in a sort of vice - like the Sota - and use this grip to apply pressure to the record and bond it to the platter, whatever the shape of the latter) and ‘weights’ (= devices that simply sit on the record, grip nothing, and apply no pressure other than that created by their 350g weight).
My question concerned ‘record weights’ in this sense, and was directed at those who have experience of them. It was: given that these weights clearly do not give priority to binding the disc to the platter, but given also that the record and the platter are nevertheless in contact, to what extent will the nature of the platter affect the functioning of these weights? The aim of the question: to clarify whether these weights do their job irrespective of the platter material or shape (personally I would be rather surprised if this were the case).
The HiFi Tuning VRO weight actually stands on three pin-like feet (two in wood and the third in platinum); the main body of the weight is not in contact with the record. Have a look: http://positive-feedback.com/Issue52/analog.htm

Peterayer - interesting hypothesis of yours that when people report an improvement on changing from a screw-down clamp to a record weight (of the type we are discussing) this may actually be due to some sort of 'decoupling effect', i.e. the record weight, precisely because it does not optimise transmission of resonances through the spindle/main bearing channel, may in fact help to stop bearing noise being transmitted upwards through the splindle into the disc.
You conjecture that, the noisier the main bearing, the more likely it is that a record weight (as opposed to a clamp) will have a beneficial effect.
Of course, it is true that some turntables have noisier main bearings than others, but surely practically all main bearings produce some degree of resonance or vibration. So even our SME turntables (mine a Model 30/2) - with their fantastic main bearings - are still producing some noise, albeit to a degree that we would normally consider negligible.
So I wanted to ask: as a long-term SME user, have you ever tried a record weight as an alternative to the SME reflex clamp on either of your SME tables? Have you ever tried either of your turntables with no clamp at all (i.e. leaving the SME clamp off)?

Many thanks, Peterayer, for your interesting post.
It does not surprise me that playing records on the SME without some form of clamping gave a less satisfactory result than using the standard reflex clamp. This is also my finding. And of course if you leave the washer in place when not using the clamp, the results will be dire! In that case the disc is simply not stabilised and will in all probability wobble (this would be the same on any turntable). You will also have changed VTA.
Personally I had always used the SME clamping system on my Model 30 (it was no stranger to me since I had previously used the Sota Reflex Clamp on a Goldmund Studio). About a year ago I happened to use a record weight (the Sutherland Timeline, which has a thick delrin base so that it can be used for disc-damping purposes) and found that this also worked quite well. The result was different from that obtained with the SME clamp: more laid-back, maybe in the end not quite as clear. I continue to prefer the SME clamp on most records, but I have begun to think that a record weight could also do a very good job on the SME.
Since the Timeline's disc-damping function is more or less an afterthought, I suppose that one can do better (read: Kuzma Ebony, Hauer-Analog Bubinga or HiFi Tuning VRO).
So the question is whether one of these (supposedly) optimised record weights would do a better job than the SME clamp. My money is on the HiFi Tuning VRO, which appears to be a carefully thought-out device.
Regards,