Yep, it's too late for those. Turns out a 3/8" wrench fits almost perfectly, but that nut rounded off. I wasn't able to get it off with a fat pair of adjustable wrench either.
I got one side done, though, and that went easy. The nut unthreaded with no problems. I suppose I'll have to run a new hard line from for that side, since that nut will be mangled when I get it off. Bah.