Try two pellets first and see what kind of accuracy you get. After you tune the scope or sights in with two pellets, then try three pellets and see what happens. Unless you are shooting some extreme distances and trying to take some monster thick skinned beasts, I would think two pellets will be all you would need. Although if you like spending the extra money and the recoil of three pellets, then have at it.

Like already said, since you're a bow hunter you are well aware of the need to get animals in close. You have the best of both worlds and a great rifle. Good luck with it. And Welcome to the forum!! nice to have new posters.