I'd just pick one that is reasonable, and mostly that will run reliably, and then tell your bro to start making dust based on what's going on there.
Heck, he can start on the wing regardless, without any real mods, other than what has been mentioned about making the bell crank sound.
I turned mine around and the flap pushrod exit's inboard because of it. No big deal, works great. My C/L adviser said I should make the up line forward, and apparently there is some theoretical advantage to doing this (don't kill me if you disagree, people!!!!). I just followed his instructions:
Up line forward
Cut off 1.5" from nose
Bush lead outs on bellcrank
More elevator throw than flaps
Silicone Uniflow tank to sliding height mount
Add tip weight box
2 degree wedges out thrust under engine mounts
Check, check, check, check, check, check, check!
Showed up one Friday to Whittier Narrows with my C/L Adviser. Freaking OS.40 FP started on the FIRST FLIP after being stored in a plastic bag in my shop for like two years! IMPRESSIVE!!!!!
Ran perfect on the first flight, 4-2-4 running through maneuvers.
I spent the next few weeks tweaking a small twist out of the wing a little at a time, and it flies fantastic now.
I really couldn't be happier with it.
I only pancaked it one time so far, Tim Westcott Syndrome (TWS), where I made a loop with a -0.5' pull out. Ooops!
Minor damage, wheel poked a hole in the wing, busted off the rudder, tail wheel angry, etc. About 1.5 hours in the shop, and only my ego was still damaged.
All good!
R,
Chris