ORIGINAL: ArrowMike
If you want 63 lbs just buy a 60 it should top outabout 62, It will also shoot better than a 70 cranked down to 63. That's what i did.
IMPORTANT! Not all limbs will top out higher than maximum listed poundage by themselves! I have a set on right now of 70lb SBXT limbs that only top out at 69.5lbs. A few string twists and I am up over 70lbs but you really need to watch your ATA and BH! Most limbs shoot best at peak draw weight but that does not mean they shoot poorly at the lower poundages.