So with flare wrenches squeezed in opposition, you still deformed the line nut? Or did the joint break loose OK, but the nut seized the line? Impact seems to help where the caliper is a good solid thing to work it against, but where the flex lines join, there's not that advantage.

It has been years since I've done flex lines, and I remember little about troubles, but that just means mine were less rusted than yours. I'd be tempted to apply heat, but very careful about making sure the pressure was relieved and even more careful to keep from starting a fire.

I've also been able to use the clamp from a flaring tool to safely grip lines, but haven't tried that yet on the 3/16 cupro-nickel brake lines. Did you replace yours with the copper rustproof lines? I didn't address your question on the extra length and folding it out of the way, but my guess is if you're pressure bleeding, with 3/16 OD lines, you can force the bubbles all the way around the loop.
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Art Benstein near Baltimore

Today a man knocked on my door and asked for a small donation towards the local swimming pool, so I gave him a glass of water.