Thanks for the info John. 7/32 = 5.55 whereas the original 4 gauge = 5.189 (round it up to 5.2mm). The latter wire fits very neatly in the wing gear sockets already so really want to avoid drilling out a tiny bit more. However, 7/32 may be a fallback plan.
Tried bending this wire before in a vice - it doesn't work very well. Really need the proper bending tool for those sharp right angles too.