I don't know where you'd go to see plans, but to make a light, straight, rigid LE for a Ringmaster, a nifty way to do it is to mold the leading edge from sheet, then back it up with shear webbing to make a mini D-tube. That gives you nearly as much stiffness in both bend and torsion as a solid-balsa LE, with much less weight.
Of course, backing that up with some CF will make it even stiffer...