1. Limit the range of shot you take to what is realistic good accuracy for the handgun you're shooting.
2. Wear ear protection when shooting even when hunting.
3. The Contender is accurate enough that it deserves a scope. Personally, I like the barrels with no iron sights if they're going to be scoped.
4. You're wise to get a muzzle tamer for the 45-70. Just make sure whatever scope and mounts is up the punishment it will take. For handguns with recoil of that degree, I go with SSK Industries' T'SOB base with 4 rings and a Leupold 2.5-8X handgun scope. Also, Lock Tite the base to the barrel; you don't need to Lock Tite the rings.
5. If you get an Encore handgun rather than a Contender, your cartridge options will be much greater. Of course, the Contender is a bit lighter and has a more elegant way of handling rimfire cartridges. By the way, I prefer the old style Contender over the G2 since the trigger is so good right out of the box.