hey keen sailor, your lazy jack set up is very poor. you should as frant says have battens ( I used 2 pieces of 16 mm conduit with timber pushed inside sewn into canvis bag. with zip full length .
support the lazy jack lines from the mast and fix in 3 points along the sail bag( you will have to tie the bag to the end of the boom). This allows to have boom hanging from lazy jack lines( you can swing out of the way) and have pin through mast track to hold down slugs. you will have to alter the lazy jack bag to accomadate .
This has been one of the best improvements in cockpit area to my boat as I can unhook mainsheet and clip to side stay with out having to have rear stay tensioned( also out of the way) VERY handy for fishing and storage of main on boom full time
with a well silicone sprayed slug track uphaul and down haul are 1 person and very fast.

what sort of boat ?