Pylon and motormount in one for RC gliders with glassfiber fuselage

Pylon for my Multiplex Super Alpha (aka Nimbus) from 1977 GFK rc glider, mounted on top of the fuselage with 6 mm bolt. I drilled the front hole up to 5.5 mm and screwed the 6 mm bolt into it and cut off the head. Just enough thread to be able to fasten the motormount with this 6mm thread and nut to the fuselage.

If you think 6mm is to much, just use a 4 or 5 mm bolt and nut for the front hole.

I used 4 mm bolt and nut for the backhole.

The rest of the 4 mm front hole that goes t