I cut the LH flap/aileron panel into two pieces at the flap to aileron junction and started fitting the top aileron panel on the LH side. I sanded down the shearweb pretty much all the way down to the line that I made representing the inside skin of the upper trailiing edge. There are a lot of variables that can be adjusted that affect the fit of the aileron and its ability to clear the skin while moving its full travel. I am still working this all out in my head. Not quite as easy as it sounds in the instructions.