After the primer dried last night I could continue with the skin, first edge rolling the leading edge and then removing the blue plastic before I mounted the skin with cleco’s.
With a small file I enlarged the mismatching holes in the skin and reamed them to 4.1 mm to accept a 4 mm rivet. This was necessary on the right side but to have the elevator symmetrical I also enlarged the left side holes, so 12 holes in total:
I wanted to be sure that the 3 small support plates sit perfectly I used a WIFI endoscoop to verify it:
With 5 AN4 bolts (with tie wraps around them for better holding them) I bolted the elevator to the horizontal stabiliser and clamped both components together and realigned the cleco’s to have a perfect alignment: