I didn't try flattened but that would help. I did wind up cutting the smaller ones on the worktop, and flattened would be good there. Today I stripped a bunch of old battery cables and just did em on the work bench.
Hanging in the corner worked good, but needs a plastic corner angle about 3 inches on each side and 3 ft or so. It keeps them in place and saves having to flatten them to keep it lined up.
Thinking even now on a good flattening process though, how do you flatten yours ?