More to the point, the cartridge isn't complete overkill for a sub 200 yard deer, but it's power and trajectory ARE wasted. Even a 30-30 would accomplish pretty much the same thing under those circumstances.
So pretty much any bullet will do. I would stay away from the plastic tipped fast openers. Cup and core is cool, but go heavy to slow it down. Bonded or all copper is probably best, but needlessly expensive.
My first priority with this cartridge at those distances would be to slow it down. Minimum loads featuring a 150gr bullet at around 2650 would be a best case scenario.
The 7mag is a great cartridge, and I've seen hundreds of Mulie, Whiretail, Pronghorn and Elk taken with it. You're over gunned to be sure, but the Ruger is a great rifle. Happy hunting and post us some pics!