I did exactly that change on the larger BUSA Eindecker.. made the horizontal closer to the scale size, and also the vertical, both converted to full-flying.
The image is another one in my club done up in the early "stealth" cellophane covering tried in 1915..
Flying tails and wing warping. Based on the BUSA kit.
Wing warping didn't work all that well, it requires a very loose wing structure..