Hey Al,
It's really hard trying to remember back to all my measures & well, just how I built some of the sub-assemblies, not to mention I don't have my bomber on hand at the mo but....
Pic-4, I don't remember taking any material away from the bottom or top of this part to fit.
Pic-3, 18mm seems way too high, maybe around 10mm tops, but don't hold me to that exact measure. Can anyone confirm this?.:confused
Stu