And how cumbersome is it to tie the mono leader to the braid? Do you have to do it a lot, or only when the leader gets too short?
Welcome to UB. Tying leaders to braid is not cumbersome if you practice tying them enough times.
If you choose to tie on a leader, choose the one that has the smallest profile but highest knot strength.
I have been experimenting with different joining knots for years, and I think I may have found the best and strongest knot that suits my style of fishing. That knot is the FG knot.
It takes some practice, but when you get it, this knot is awesome. You only need to tie it once. Only time you need to re-tie one is if your leader gets too short, or its broken off. But the break off will not be from that knot.
Good luck on your knot journey.