I'd really like to hear how 15 compares to 21. I still can't decide on which one to go with. I have a lot of 6" B&S pads, if 15 works well I'd rather go that rout.
This is very interesting. I used it on Flex 3401 with Optimum MF pad and had minor dust. I'll give it a try with LC purple wool pad to see how it does.