What has to be accomplished is to make the reluctance between the two generator magnets greater than the reluctance between the two poles of a single generator magnet.

This was already discussed back then but i will add using the idea of change of reluctance between magnets is tricky here.

If one made a screen as i proposed balancing magnetic repulsion with iron plate of proper thickness and placed it between two attracting magnets to cut the field effortlessly, it is not ideal to speak of change of reluctance, we can make a parallel with two batteries in series adding up in voltage (and thus in current overcoming the resistance more). If we now add a third battery in between opposing the two batteries if voltage of the third battery is large enough it will stop or reverse the current direction. But is this change of resistance (equivalent of reluctance), yes and no. In similar manner when two magnets attaract and we place a third magnet between them that repels both, flux linking the two magnets is broken. It is broken by the presence of another field which repels the flux on both sides. This may be called increase of reluctance but it is not exactly correct. Reluctance is ability of a material to conduct the magnetic field, technically, material wise, reluctance has decreased (air was replaced by iron), but since those domains are polarized in opposite direction, original flux has been broken.

In any case, there is no doubt such shield can be made and two attracting magnets can be cut with no effort or minimal effort.

As for Don's device, i wrote before, he made wild claims about the alleged output, he claimed 50kW PER COIL. Just pure madness. But it was typical for Don to make such wild claims.

As i wrote before magnetic field passes through everything even (weaker) opposing magnetic field. Unless you got 'magic' ceramic like this https://www.youtube.com/watch?v=_FABlYE9Vhc

So that screen even if made of such special material cannot be a thin vinyl LP as Don shows. In other words unless Don really stumbled upon some incredible chemical compound (he was a chemist/geologist) that can shield magnetic field with such thin layer that device was fake.

Shield needs to have certain thickness, at least 1-2cm, and that is a problem cause magnetic field falls with square of distance.

And there needs to be few mm spacing between rotating shield and magnets, so that adds up to minimum 2-3 cm between attracting magnets. That is quite a distance and much of the flux will not go through the gap in the first place (no shield present). But still, it is a viable method, just needs lots of precision to exactly balance the forces.