The OP asked about the Floating polyleaders...
I tried one to see if it might help keep my line on top better. It actually was worse, because the larger diameter (than the fly line tip) was more prone to getting caught by micro-eddies, etc. and drowning.
Hence, I found no advantage to the Floating polyleader, and it seemed to be worse than a regular leader, IMO. You still need whatever length of regular leader is appropriate, anyway, as the polyleaders are more of a line tip than a leader.
On the other hand, I really like the sinking polyleader.
--Bill