Teasing: Point #3 seemed more about the receiver, not the barrel.
Call me "Mr. Lucky", but I've never had a problem with the bedding of a receiver.
I use kitchen wax paper for my shim material. I cut a 3/4" strip and fold it back and forth until the thickness is such that it takes maybe a five-pound pull to install it near the front end of the forearm. Trim with a razor. The wax sorta melts together after a few shots and stays lightly stuck to the barrel. Being wax paper, it doesn't attract or hold moisture.
I've done this deal maybe a dozen times over the last forty or so years. It's always made some improvement. Once I'm done with this tweaking and some load development and I can get three-shot groups inside one MOA, I quit messing and go to hunting. I'm not a benchrest target shooter.