To connect the wire to the mono leader I us a small, high quality black ball bearing swivel (I like the Spro brand) . Connect swivel to mono with a palomar knot. Connect wire to swivel with figure 8 knot. Connect wire to fly with a two turn non-slip loop knot, which works well with all of the knotable coated multi strand wire that I have tried.
I have used this for pike as well as toothy saltwater critters. I have gone through a week of 9 hour pike fishing days without ever needing to change the mono part of the leader.
Works great and I don't need to cut back the leader to change wire. The swivel does not interfere with casting. It also has the the benefit of preventing twists in the leader that may develop from casting some flies. Wire changes are much faster to accomplish. Don't use a silver swivel because sometimes fish will hit that instead of the fly and cut through the mono leader.