More great advice from everyone! I appreciate it.
Something with a fan definitely does sound like a good idea, and it's interesting to know that Rx lenses aren't too expensive. Might be worth looking in to. Rx goggles might be a good investment, though, that still leaves the problem of being shot in the face, which doesn't sound like a great deal.
As for my other issue of aiming down iron sights while wearing a mask, any tips on that? Is it avoidable, or should I just give up on the mask idea?
Edit - Didn't see the tip about cutting out part of the mask. That could work. I also saw some flexible masks? Are those any good?