If your worried about getting too close to the top you dont have to fully sink the channel. as long as the the flanges and part of the web are sunk. ...
I was at the NY knife show saturday and you definitely have to have a budget for this. Some of the customs there were 3-4k. I have a friend who makes...
aluminum tape can be used to ground your line. The alternative would be to connect a 12 gauge stranded wire to the wire in the 4" flex if you go down...