I trimmed the flanges back to the final width of 7/8". Near the leading edge I narrowed the flanges further to about 5/8" to clear the nav light recesses in the wing tips. I also rounded the very LE of the flange to help with the fitting of the tip. I then put the LH tip in place just for kicks. Still a long way to go before it fits the way it should! Patience I guess...