You're not going to notice the difference between 6061 and 7075 aluminum with a quality set of rings. While technically 7075 is a stronger material, in so far as mounting an optic, it's unlikely that that you'll reach either one's threshold.
I don't know anything about Hawkins' products so I can't vouch for their stuff. I have used multiple rings and mounts from Vortex, Burris, American Defense, Badger Ordnance, and Nightforce that were made from both materials and had zero issues