I put about 10 miles on it this morning and it seems to be holding up fine, no signs of wear or tightening up.
It is a bit more massive than I'd like. Not quite a kludge, but not exactly a fine instrument either. I can say it works, it spins almost feely with no cable, and during the ride I grabbed the cable with my fingers to see if it would misbehave. It didn't skip a tooth or jam in any way I could tell riding.
I need to look into the cable connections a bit more closely. I hope I can buy some that fit a bolt that is readily available to keep cost down.
I'll let you know what I find out.