On my Pitts model I did all the tubing structure as a weldment and inserted that part file into an assembly to add the fittings. No automatic trimming for those parts and I made no attempt to create perfect fits between added parts and the tubing structure -- those mostly get done by hand anyway. I highlighted some of the faces below to show what I didn't trim;
This is the weldment by itself, structure only -- even the tubular fairleads aren't modeled here.