Dan,

I would take W-6A, leave the top alone and taper it from the rear spar to the aileron spar, W-7 leave the top alone making sure it is just below the top of W-6A (1/32") and adjust the bottom curve (almost flat) to fit the aileron spar and do the same for W-8. After they are assembled, take a sanding bar and sand the ribs so they form a smooth transition to the tip on the bottom. On top from the mid point forward W-8 will be much lower than W-7 at the leading edge. See P2 above and you can see W-7 behind W-8 (W-6A is not visible along the top). Since the kit forward spar is not in the scale location the taper of the spar from W-6 out to the tip is different than the full size. The leading edge also tapers from W-6A out, a gentler taper on the bottom than on the top especially from W-7 to W-8. See P-1. W-8 does not meet with the aileron spar but meets with the tip bow just outboard of the aileron spar tip anad is supported by a gusset. P-2. The rear main spar starts to taper on the bottom at W-6A all the way to the tip bow.