I like the elongated B2 & B3's and attach them to the permanant dock as they rest against the planking & joists/beams and still stick out beyond the pilings to keep the boat safely cushioned . I just clean them every couple weeks with suds , brush and Magic Eraser. As every offshore fisherman knows they make great easy-retrieve anchor buoys , and I've used them in bunches to move 1+ ton block moorings quite a distance.
But I still use TaylorMade or similar 10" dia. fenders with soft, washable fleece covers to attach to the boat.