I got the B Series about 10 years ago. I think the vented came with weights but I'd have to see if I can find them. I think they were meant to help with axels. I never got that far. I'm mostly trying to get better at the stop and starts for a clock rotation (I don't remember what it's called), ladders, and bicycles. (Not sure if that's what those are called either.) Axels are a bit beyond me right now. I might want to wait until I can get to York, PA to draw on the experience of the flyers there at STAP to help me on the journey. They've got quite an active group with a lot of good dual and quad flyers. It would be nice if we had that community in Upstate NY. (NYKE isn't that active in the Albany area.)
In any case, it's just fun to get out there and fly - glider kites, single lines like the 61/49, duals, and quads. I like 'em all! (I'm thinking about the Blue Moon Ichiban but I could get two duals or quads for the price of the Ichiban.)