I shoot a 43 lb. I use an axis 500 I have two wraps on it, and 125 grain Broadhead, total arrow weight for me is 435 gr. It works out for me. It calculates to 10 gr's per inch. If you do anything between 9 and 12 to do all right, sometimes it helps to leave your arrow longer, but the best thing is to bear shaft tuning your arrow. I have used the axis 500 because they are high penetrating arrow.
Though the others that will give you some advice because there is quite a few on here that shoot between 40 and 48 lbs.
Pastor Carl