You might ask Al Rabe about dihedrial in top of the line CL stunt airplanes.  Tapered wings bounce around in the wind less than similar rectangular wings.  I'm building a fairly close to scale Tipsey Junior for Old time Stunt.  I has a low wing with a little dihedrial, enough to get the leadout guide up to where it needs to be in relation to the vertical CG.  Friend has one finished and it flies nice.