The grains is not determined by the game you hunt, but more by your bow/poundage and the arrow it self. I shoot 100 for everything, but that is just me.
I had a whisker biscuit and liked it for ranges up to about 35 yards......anything past that it seemed like a knuckle ball and I lost some zip and and control. For two years now I have used a ripcord and I have the same control at 20 as I do at fifty and can say truthfully and mistake I do make is not due to my rest. Just my two cents.