I've got a pair of olive cutters (look like a pair of pliers in a way). They make it so much easier to remove an olive - way better than with a min' (typical 6") metal bladed hacksaw.
Monument and Ox Pro (amongst others of course) make them. They are designed to fit over the olive and then you simply squeeze hard to penetrate/cut the olive; after-which it can be removed. You'd need one pair for each pipe diameter.
Tool Station have Monument; Amzon both.
Some olives will cut more easily than others.., brss being the hardest. You can't use these cutters on steel olives..