I have fitted the fiberglass wingtips (with screws and nut plates) to the wings of my RV-7, and am now wondering what the best material is for finishing the intersection with the aluminum wing skin. It needs to bond to the fiberglass and be sandable. The instructions just say epoxy and flox, but there are lots of epoxies out there, and not all are sandable. Any suggestions? I have some West Systems epoxy and microballoons, but not sure either of those are appropriate here.