8-foot rotor makes 50 square feet swept area. The tail has 3 square feet of area, so the ratio is 6%. Furls okay.

Note that the offset of the rotor axis from the tower axis is 8 inches, which is proportionally more than normal.

Tail size is worthy of a FAQ, but a worthy answer would be one that is simple to apply and works 99% of the time (90%?).

That answer isn't out there at the moment, and I don't have one to offer, either. Goodness, I've tried.