Well, you will get the most accuracy from drill and tap, good luck. The Bent Bolt Mods look cool too. My 91/30 is pretty accurate, it would do well with a scope and I have thought about it. I would go with the authentic soviet mount and scope and get the bent bolt, make it look like a real 91/30 sniper.
But you could buy two maybe three more Mosins for the money it would cost to do that.