On my B323 with the LazyPack, the starboard lazy jack line chaffed- and broke- rather quickly where it goes through the spreader. I placed a twisted D shackle in the holes so the lazy-j runs through the u-shaped(smooth) part. You'd have to place a shackle to hang a block there, so figured I'd try just the shackle first. Works okay so far.
I took the upper ends of the lazy jacks off the mast, joined them to a third line that runs up and through the block in the mast a few feet above the steaming light. The third line I ran to the cockpit to a line stopper. I can slack off the lazy jacks when sailing, but also opens the bag wider when you drop the main.