I used B2 on the old 2 puck 5.7 and 6.0 Ski Nautiques. I use B2 on everything except the new 5.3/6.2 SN where I use B1. I just feel the new engine single puck combination is slightly firmer than the old setup. I'm still using B2 on the Centurion with single puck, but they have not switched to the 5.3 or 6.2 yet (the one I ski behind is a 6.0), so I don't know if that will be a factor or not. In the last tournament at Okeeheelee that I skied, I ran 3.5@35 behind all three hulls (5.7 MC with 2 pucks, 6.0 Centurion with 1 puck, 5.3 Ski Nautique with 1 puck). If you include the Malibu, all 4 boats are pretty great these days and we have to get really picky to find issues...