Dear Georgina,
i also have to apologize for my somewhat rude reply to your commentary. It was in no way ment to downgrade what you have to say about the whole issue.
My point is, your are talking about spin, and i am left with no information what you understand in detail by 'spin'. Firstly, i tried to visualize what Peter replied to me. He spoke of the particles flying to the left and to the right. So i imagined them as rolling along the propagation axis (one of them; the other flying in the opposite direction, but having the same rolling 'spin' - clockwise).
Now, is this rolling already the spin Peter and you talk about? I had to assume a yes, because Peter told me one can simply visualize the spin properties (north and south pole) by imagining the particle as 'painted half green and half red - each hemisphere with one of the colours).
What i assume to be the spin in your visualization, is the fact that those waves (electromagnetic) produce tales and hills in a regular manner and the two components of the wave (electric, magnetic) always are perpendicular to each other (see http://www.upscale.utoronto.ca/GeneralInterest/Harrison/SternGerlach/Polarisation.html - second picture, transverse waves).
What seems to point to the left side of the red arrows (ahead, front) seems to point to the right side - when watched from the back perspective of the illustration. The question is how this is translated physically in such a way, that the frequency of the waves (in the Bohmian experiment) do not randomly trigger the detectors to produce a 50:50 change for spin up/spin down, but do it in an (anti)-correlated manner (if both magnetic fields are in the same direction or in a 180° relation).
Be aware of something: One can do the experiment not only with electrons, but also with silver atoms (or hydrogen atoms). Only the 47th electron in the silver atom has the net magnetic moment needed for testing the spin orientation of that particle. So the question is, how are the forces of that 47th electron transferred to the detectors?
I will wait, until Peter replies, before speculating further.
Best wishes,
Stefan