Hi Stephen,
I'd use it with the veteran barrels. If someone wants them, the price is a reconditioned set of vintage barrels and pistons. If anyone comments, it will be on a rally where you are actually riding a bike you have restored, having so much fun you won't care what other people say! The only downside is the sparse finning on a veteran barrel and the conservative port and valve size. Just don't push too hard.
Don't weld the cylinder if it has been bored - the correct order is heat first, machine last. Welding risks distortion. Try JB weld if you're worried about cosmetics. After all, the worst that can happen is that the fins will fall off on the ground.
Have fun,
Leon