Tom,
Yes you do prove my point to Doug above, but I can see why. First; I've made it clear a dozen times I agree Bells maths is a tautology. Missing that explains why you miss the other key points below;
1. Spin considered in a centre of mass rest frame has a flat equatorial plane disc. That's the case of detector field electrons (Polariser/analyser/photomultiplyer).
2. Spin as conserved Angular Momentum when also considered with conserved LINEAR momentum describes a helical path, as I described in detail last year. Except that I now also describe the transfer of OAM as 'measurement' on interaction of the stationary and 'arriving' case, in 'time' (Hopf) and with TWO 'global' sets of y,z axis rotational freedoms.
Those geometries are now at least the same 'size' as Joy's who seems to describe a very similar thing as 'tortion', which I'm sure may be just as valid. But then our descriptions seem to further diverge; I show how a real classical and causal physical model (the rotational speed distribution with latitude) COMPELS the Cos^2 "prediction of QM" which Bell said is impossible, and Feynman said;
"We choose to examine a phenomenon which is impossible, absolutely impossible, to explain in any classical way, and which has in it the heart of quantum mechanics. In reality, it contains the only mystery. We cannot make the mystery go away by "explaining" how it works. We will just tell you how it works. In telling you how it works we will have told you about the basic peculiarities of all quantum mechanics." (Lectures Vol 111, 1-1).
Now ignoring my essay and re-stating Joy's description reduces to; "I don't believe that as I believe something else", If your disagreement with my derivation is to have any validity at all you must show why. i.e. specifically WHERE it's wrong, or that it doesn't produce the Cos^2 relation with 'angle change' which I show it does (not to mention the 'reversal' at 90 degrees, and the uncertainty of direction at the equator).
To find a point of agreement, most will of course see it as 'ambitions' because it allows convergence of QM and SR. What it seems you refuse to countenance, apparently always jaundicing your view is the possibility that the 'common interpretation' of SR is constrained (given spatial limits below infinity) to allow QM to be consistent with the postulates. In physics NO possibility should be 'ruled out' or theory re-tested at all opportunity for a better interpretation, even SR. What doesn't kill it makes it stronger!
If you read my post to Doug above then more carefully read the essay, with those blinkers off and mind wide open, you should pick up the bit's you've missed. I promise it won't hurt! (I do admit if it were a paper some bits would be more clinically explained).
Best wishes
Peter