I just read up to here and I see you got the over current latch up issue fixed, so I guess disregard my last.
As far as current sensors go, I wish there was a reasonably priced hall sensor for 1000A so far all I can find is like $100. I am probably going to read of of my shunt instead, but at 75mv full scale, that is going to be difficult to get an accurate trip point set. Any recommendations for either option?