I rough cut the access holes in the fuel tank wall and trial fitted inside the tip. I still need to match the holes to the doubler plates, but I'll do that once I've match drilled the mounting holes. I'm happy with the results so far, which should give me enough reach to glass the inside of the wall as well for proper strength and leak resistance around the joins.
My plan is to make the wall a relatively loose fit, initially bonded in place with some judiciously placed dabs of resin and Aerosil while the whole tip is cleco'd into the wing. Once that sets I can be reasonably confident the shape is right and that the remaining layups won't move out of place when I return the tip to the wing for final curing.
