I figure this would be a smaller hole in the the FW and less mess. I plan to open up a hole in insulation and ss foil, then glue that edges of the opening to the FW. Let cure, then drill the hole through the FW. This will lead to no mess behind the insulation.
EAA Chapter 1093 member
FaceBook Page: Ken's RV-14
RV-14a (serial number 140073)
Plane at hangar and the wings ON.