I am not sure of the centershot measurement of the pronghorns, but I would guess you are going to be underspined with 50/55's. You are likely pulling just over 50#'s @29.5". I would guess 65/70's. You might get away with a 60/65 if you are shooting 125gr pt., or you may need a little more if you are using a heavier point. You might try one of the test kits with multiple spines, or I sometimes will buy towards the higher end and sand the middle 1/3 of the shaft a little at a time to experiment with different spine. Of course you will need a spine tester to do that. If you are going to shoot woods seriously, you will be better off buying or making a spine tester. Careful, wood arrows are addicting!