Ditto..n how much weight are you pulling there at 20"? If its not pulling at your intended weight at 20" I'd say you can pull it another inch and check it/exercise it,and if all is still well you can pull another inch etc...till you are pulling your intended weight....otherwise if you are pulling your intended weight at 20" ,then its just a matter of careful full length same number scrapes each limb to reduce weight,and monitoring your bend as you go down inch by inch till your at your draw length...and when you get to two inches away from your intended draw length start shooting it in at some short draws first and slowly out to your full draw...the reason for this is you'll lose some weight shooting it in(due to set) and final sanding to seal it