The 305 G-claron will cover 7x17, with some movements. It is a very sharp lens with a decent amount of coverage. My understanding is that it is a single coated symmetrical lens that is sort of the optical descendant of the dagor design. Badger Graphics still had some of these new last time I looked at pretty reasonable prices.

The red dot artars have considerably less coverage, are also coated, and are incredibly sharp. I doubt if a 12" artar will be suitable for using on an 8x10 if you anticipate using any movements.