IMO a 158gr bullet will do just fine for your purpose. I would suggest a hard cast bullet with a wide flat nose though.
Since it seems you decided a 158gr bullet will do, if you're reloading I would suggest the
160gr Hard Cast bullet from
Cast Performance. They are part of the same company as the
Grizzly Cartridge Company. If you don't reloading I highly recommend their ammo. The bullets from
Tennessee Valley Bullets recommended above are also a good choice.