I'm not sure why you would want to do that in a 440.
We lower the topping lift
and find the boom sufficiently low enough to open an close the sailbag comfortably.
We had a sailbag made with a course zip and have a long strop attached which we use to slide open and closed. We never have a need to to climb the mast
to hoist sails
What we did do, is to add steps up the mast
to the radar
dome, which has been great for removing and refitting sails
We also put reefing marks on the sail and on the mast so when reefing we simply align the marks on the sail to that on the mast. The positions make it easy to reef as one doesn't have to keep checking if the reefing blocks are ramming against the boom.
Never thought to lower the boom though - it has just the right clearance for me.