I have the best of both on my Suncat with mid-boom sheeting and traveler. Two years ago I went to a Garhauer two speed block setup that they call a vang, must be for a very large boat. It's part number 25-2, is $200 and I used 80 feet of 1/2" line. With this setup you have 3to1 for jibs and 6to1 for fine adjustments and plenty of power for when your close to the wind. It sounds like the best of both worlds and it is. You have two lines coming out of the lower block with a cam cleat on each, you pull both lines at the same time for 3to1 and just one, eather one, for 6to1. I know it sounds confusing but it works great and would work on any boats main sheet. Go to Garhauer and take a look for your self. I used my old main sheet for a boom vang, that is what I was looking for when I found this two speed set up. Let me know if you have any questions.