Read Midway's reviews of the Weaver 301 and 301S (silver). Guys report it fits the Super Blackhawk easily, but that some fitting is required for the Blackhawk. I bought a 301S for my SBH, but haven't installed it yet. I have one of Weigand's no drill bases on a 5.5" Redhawk, and it is great. If they make the same for 7.5" Blackhawk, that might be the better way to go.
As far as scope is concerned, I have a 2X Leupold on my Redhawk, but am thinking about switching to a red dot.
Cogito, ergo armatus sum.