Direct drive vs belt vs rim vs idler arm

Mosin,

Location of mass matters, and it matters a lot.

Interesting.......I must admit I had never really considered this?
It makes sense?

Mosin -
Absolutely right, I used mass loosely. I read somewhere the EMT idler has a platter of 5.5kg ( same weight as the copper mat on my deck ) but due to its weight distribution ( 16 & 1/2" platter ) is the equivalent of a 50kg solid platter. Although not as radical my TT has an inverted bearing with a substantial subplatter which is an inverted truncated cone (frustum), so most of the mass of the 20kg platter is between the inner and outer grooves & the thickness increases inside out ( and below the bearing point ). So yeah the effective mass of my TT platter is well in excess of 20kg.

Okay, let's go further. Do you think a special merry-go-round could be built for the little girl, so she could spin as many kids around as you can?

This goes to torque, and how one might approach building a turntable with a low torque motor, yet having mass applied so that performance would equal a turntable with a high torque motor.

I suppose the point here is that there are quite a few ways to skin the proverbial cat.

Dover,
As 'stylus drag' must vary with the modulation of the grooves responding to the complexity and dynamics of the musical performance.......it would not, I think, be a constant?
If you merely adjust your speed-controller to hold the Timeline constant with the cartridge tracking........it would be interesting to see where the Timeline 'mark' would be at the end of a whole side of a powerful symphony such as The Royal Ballet, The Three Cornered Hat, Pines of Rome or Witches Brew?

Yes I agree, thats pretty much what I proposed for testing to quantify the variation between that minimum and maximum drag levels and the impact of a piece of music in total...I think you misread my syntax ( no pun intended ). ("how consistant" , ie I meant range of variation. )