If so, you don't need to worry much about jacks going all the way to the aft end of the sail. It will fall in line with the forward section, which has more volume anyway and is more in need of being contained. Is the sail loose-footed?

My boat is very different from yours but the problem is the same and this may give you some ideas: My sail cover attaches to top of the boom and can be rolled up to stow alongside the boom when underway. No need to stow it in a locker. The cover is between the sail and the lazyjacks when the sail is covered... So the procedure is we dump the sail, unroll and extend the cover up along the sides, and zip it on top. The lazyjacks stay in place. (If your main isn't loose footed, a sail cover could be made in two halves which attach to each side of the boom.)

Also, my lazyjacks attach to the spreaders about 2 feet away from the mast, and chafe is a non issue when we sail. There is no reason to attach it to the mast unless you don't have spreaders, or they aren't well attached at both ends. The boom rises when the sail is full so that induces more slack in the lazyjack lines, and I don't see a need to loosen them. I don't have a backstay or topping lift... The lazyjacks are 5/16" line and double as topping lift.

Here's an image that shows how mine is rigged. The lower spreaders are visible, but the aft jacks attach to the upper spreaders. I attach the main halyard to the boom-end fitting when anchored or moored, so I can snug it up to stop movement without stressing the spreaders. I'll try to take some better pictures if I visit the boat this weekend.