I am designing a bipe and i need to know how big the H and V stabs need to be in relation to the wing area.

On a monoplane i use 18 to20% of the wing area for the H stab and 9 to 10% of the wing area for the v stab.

My friend is storing his 1/4 scale tiger moth in my shop and i noticed the tail seemed small for the wing area! it has 2 71x10.5 inch wing 1491 sq inch wing area.
H stab is around 175 sq inches.

So thats like 24% of one wing or 12% of the total wing area.

So how do you determine the tail size for a bipe? I always though you did it like a mono plane