I second that^^^. However, it looks like you've gone too far to turn back now and can dig it back up next year if it doesn't perform as planned. As for the tape though, I guess this is news to me. Copper pipe comes right from the factory with that stranded packing tape holding the bundles together, and lots of it. I always try to burn it off for aesthetic purposes, but most do not. There are a lot of folks with a strip of regular old black electrical tape on their copper lines to check temps with an IR gun, as the copper is reflective and gives a false reading. With that said, I do a lot of commercial work with original piping dated back to the 60's and residential back to the mid 80's and the only copper failures (which are few and far between) are at or near a joint, or somewhere where the pipe is in contact with something ferrous like an iron hanger or something which causes electrolysis. I find it hard to believe that tape could be of concern. Any reason you're not running PEX instead of soft copper if you insist on building your own underground? I seem to have missed that discussion.