It is much easier to get a good shape with the loose foot. When I asked the sail maker about the additional load on the clew and expressed concern about the slider pulling out he said don't worry about it, the load is mostly at the clew even with a shelf footed main so it won't add much load. After the clew slider popped out a few times on my new main I added a strap around the boom to hold the clew down. I can tell you that you WILL have more load on the clew with a loose footed main than with a shelf foot. It's easy to deal with on my boat with end boom sheeting. Your boom is likely over engineered so it may work on yours as well but you should consider the additional load.