I got double thickness A8s through Cermag for a Distortion set and an extra thick A5 for a Seymourizer. They don't list A2s in that thickness but they might be able to make you some.
Two magnets stacked the way they are won’t work. They need to be bonded and then magnetized as one together. Which I think anybody could actually do. It’s just a means of asking I suppose.