Paul, Toucan has a simple 4-1 purchase with a 200mm wire strop at both the boom and the attachment on the mast step. The bottom turning block has a jammer, it has plenty of travel and is powerful enough. Maybe we need a gentle luff to adjust in a real blow. The jammer is a snatch block with the angle adjusted so the kicker can be adjusted when standing in the companionway. Hope this helps.
B