Rose -
I'm not a mechanic, but I do have three project cars I'm working on currently. So yea, I know a thing or two.
As far as the 6-7 hour timeline and the associated costs, that sounds reasonable. My one concern, however, is they dont seem to have the best electrical troubleshooting skills. This isn't something a lot of mechanics really do well. Anyway, I would think they should be able to properly address where the problem is before deciding the whole harness needs redone.
"Oh Lord it's hard to be humble, when you're perfect in every way. I can't wait to look in the mirror, cause I get better loking each day. To know me is to love me, I must be a hell of a man. Oh Lord it's hard to be humble, but I'm doing the best that I can." Mac Davis