When I built the Brodak Mauler I built it as close to box stock as I could. Never chacked the balance point. Second flight on the plane with Fox 35 Stunt I put it thru the pattern. When I got the Brodak 25 I put it on the plane to finish breaking it in. It wound up being Emmy's plane until Tulsa last year.
Ever since I started in this crazy hobby, every thing read said no more than 25 % of the chord for the balance point. The P-39 is the first plane that came out so nose heavy it would not turn a sharp corner. Flite Streaks were quick on controls even when a little nose heavy. Of course they had Fox Combat Specials on them.
Try the first flight and then adjust accordingly. DOC Holliday