I have not had any problems with the floating dip tube approach - I have it in the fermenter all the way through to racking. I use a kegmenter, so fermenter shape may make a difference - mine is shaped like a commercial keg, but is somewhere in the neighborhood of 14 gallons, IIRC. The model of dip tube is Clear Draught - but I would think any would work pretty well. The stainless ball float gets coated with krausen, but the pickup is below that, so it remains relatively clean through the racking.