1. Filled a few pinholes in the transition between the rear seat and its fiberglass cap. Sanded everything again. 2. Used T-Rex tape to mask off the forward spar attach angle, so I can try to trim off about 1/16" from the forward upper part of the angle that was interfering with the wing root fairing. I only had limited luck with this method, and it looks like I'll have to partially unbolt the angle, in order to file it completely.