Balance point.

AA biplane requires the top and bottom wing be included in a total chord measurement. With the swept top wing, of the Great lakes for an example, I would measure from a point half way out board from the wing root. Set up the craft in a level condition, that is with the tail up until all is as level as possible. Then using any 90° instrument, measure the distance projected to the table, from the leading edge of the top wing to the trailing edge of the lower wing. This distance is the total chord.

If you want a very stable craft, then balance the craft back from the leading edge 25% of the chord. The aerodynamic center of pressure is normally some where behind this center of gravity point. This is why we have to trim in up elevator (produces a downward force on the empenage) to maintain level unaccelerated flight.

On landing a craft in this configuration, you will need to carry more than normal speed in order to maintain elevator authority unless you have a lot of elevator surface area.

If you want a more agile rapid responding craft, move the CG back to no more than 35% aft of the leading edge of the total chord.

Hopefully this information will be helpful.

Best regards,
THC