Eganwp,
discrepancy in build caused by that thing called life which demands your responses, also by a nasty crash of the 4*60 and building a whole new wing and fixing the fuse, I just have this anti clutter rule in my head "fix the airplane that is nearest to fly first" other wise its gets too cluttered of broken airplanes.

Now for the 4*60, yes that wing is like a puzzle it’s very suitable for med CA but to make it with aliphatic glue it’s a bit tricky.
Other thing with the 4*60 fuse made of plywood and you need to reinforce the corners.

Down side with these two kits:
US60: the fuel tank is very deep so there are two fittings for the fuel line through the firewall, not must I didn’t do it but just safety.
4*60 there is a hole in the fin for the elevator joiner - tricky to cover but everybody overcoming it this way or another.

My recommendation is coming from flight characteristics of the planes on your list.
I don’t want to be the one who talked you into this kit building thing, sometimes you loose interest in the kit and that is why there is discrepancy in build.

Alex