I've just started building one of Balsa USA's Eindecker 40 kits and I'm planning on making a number of scale improvements to this decidedly "sport scale" kit. I plan to leave the main wing as is (a thick, flat-bottomed, trainer-like airfoil) but I'd like to replace the kit's current rudder and elevator setup with scale full-flying rudder and stab. The scale rudder and elevator are much smaller than the kit versions and I would consider enlarging them a bit (perhaps 10-20%) if this will improve the flyability.

But here's my question:

If the surface of a full-flying rudder is comparible in size to the movable part of a much larger vertical stab + rudder will these surfaces do the same job? Ditto on the elevator (on the EIII the leading edge would dip down on up elevator).