The wheeler toolworks great for leveling your rifle, the magnetic base helps. But any small level that will fit a flat place on your reciever will work, Just make sure you have the rifle secured so it won't move, Level your action side to side ( fore and aft don't matter) then sight on a piece of string with a weight on it, (try to have your string about 50 yards awayand use a fairly thick string) Line up the verticle and your good to go. Make sure you've set your eye relief correctly before you snug it down, Then use the bore sight methods to line yourself up for the first shot.
By the way, if you want to get the best out of this stuff try reloading also, it helps find the right load and being as you sound like a hands on kind of guy I think you'll like reloading.