The right mainsheet solution depends upon your own sailing preference, but a few general principles reign true. The farther forward on the boom the mainsheet is attached, the more of a downward effect (vang-like) sheeting elicits. The resulting elimination of twist may or may not be desirable, but it’s part and parcel of the trimming process. It’s no surprise that almost every performance-oriented sailboat is designed with end-boom sheeting.