We purchased a new main last year from Mack Sails in Florida and decided to switch from Dutchman to Mack Pack w/ lazy jacks. Very happy with decision. After sail drops into Mack Pack (bag) it still requires some adjustment but once that is done we just zip up the pack and don’t have to deal with putting on a sail cover. Mack Pack is superior to other such systems. Sail and Pack are independent of each other so no mods to sail needed. Also pack is open at bottom (2 halves clip together under bolt rope of main ) so it does not collect water. We installed it ourselves with no difficulty. .