Just looking this over and making some observations:
With a 1 inch wide magnet face equalling a 57degree duration on the face of the 2 inch rotor, there is no problem with the magnets being an equal 180 degrees apart. And they will be much better balanced if they are 180 degrees as opposed to say 150 deg. apart. It's a compromise solution, but it should work. The important thing is that the magnets are between the pole pieces of the coil winding when the points open. It's that old high school physics thing where you pass a wire through a magnetic field and make electricity. Only here, we pass moving magnets past stationary wires, with the magnetism being coupled through the coil of wire with the iron pole pieces.
Let's say the first cam lobe opens after the middle of the magnets have rotated past the middle of the coil pole pieces. No problem, we're making some, though not max juice. Then the second cam lobe will open the points again when the middle of the magnets have almost passed by the pole pieces again. The second lobe opens the points 157.5 degrees after the first lobe.
I'm assuming front cyl firing first, then rear.
Say the points opened just as the rear of the magnets passed the pole pieces. It's 156.5 degrees from the trailing edge of the first magnet to the middle of the second magnet. And it's 157.5 degrees from the front lobe opening to the rear lobe opening. almost the same. So if we set it up so that the front lobe is opening a small time before the trailing edge of the magnet passes by the pole pieces the rear lobe will be opening when the magnets are nearly centered on the pole pieces, giving plenty of juice to make a spark. The front spark is a little past its "prime" but the rear is quite strong.
Maybe the exact openings are at somewhat different points on the magnets than I give in the example, but the theory is probably valid.
I'm thinking, although I can't see these relationships clearly in the pictures of the rotor, that this is the compromise that was worked out. At kicking speeds, it might be a little harder than ideal to start, but once running, there should be plenty of spark. My experience with Lucas magnetos, where you can vary the relative position of points opening to the position of the magnets in the pole pieces says it's a very workable solution. Lucas varied probably 15 degrees or so, with no ill effects. (well, if you didn't retard them there were ill effects, but that's another story
Does that make any sense??
By the way, I missed the reference to Mu metal IP, were we shielding something here?