You may need a special setting die for those McMaster double snaps.

If you are securing these to a hard surface, another option besides snaps would be "turn buttons" or "quarter turns" or "twist lock fasteners" (different names for the these things).

You can buy double-height male fasteners that accept two females.

Bonus points: You don't need any tooling to set them in fabric, except maybe scissors and a blade to cut the hole/slits for the female side (just push the prongs through if you're using a woven fabric).

I think quarter-turn fasteners look cool and are easy to use. But I also hate snaps, they just annoy me for some reason, so that's just my opinion.