The amount of powder you need or shoots best will be determined by the rifle, the twist, and the projectile. I have a T/C Hawkens rifle that shoots great with 85 grains of Black Powder or 75 grains of Triple Seven powder. Yet my Traditions Woodsman Hawken(s) both shoot well with 90 grains of Black Powder and a roundball.
The important thing is to prepare the rifle properly before the first shot, and then know your rifle. Does it need to be swabbed? Does it get fussy about projectiles? All the things your rifle will tell you with lots of range time.