I see, so thats the way Seymour Duncan knew(1977-1978 when he supposedly did the rewind)that the magnet that was in Eddie Van Halen 1961 gibson paf was a alnico 2 magnet, so that’s why he used alnico 2 for the Seymour Duncan 78 pickup
This video might be helpful, gives a visual representation with something the guy made with iron filings.
Early-ish Gibson PAFs could be A2, A3, A4, A5. Magnet length also varied depending on year. Is there a paritcular year/guitar/sound you're trying to go for or just general knowledge?
I suppose that's a question for him. The press release material for the production pickup doesn't mention anything about magnets either. SD was making them as custom shop pickups for a while beforehand. Maybe the A5s would be too scooped, too much bass, not dynamic enough? I think the bigger winders care about more about the tone/feel at the end of the day, rather than exact specs and construction methods like boutique builders or forum goers do, and they'll do that with whatever materials they want to use.