Off topic a bit- you ever notice on forums everyone loves to offer up ways to spend your money for you? Like money is no object and it NEEDS to be done a certain way reguardless of price-after all its your money were talking about here. Why not get some custom made gold plated wire made up? Gold won't corrode blah blah!
Honestly this is over my head now, thought maybe I could help but def over my paygrade here. I am assuming you're only going to trench in the new service and you'll hire the termination? Good luck sparky