Red Tin Mucilin, Gerhke's Gink, Thebault's Silk Line dressing, all work. The trick is how much!! Wipe some on your fingers, rub it in as you pull the leader through, then pull it through a piece of cloth. Too much it will sink, too little it won't float long. Just right, they float for hours.
6/0 Uni Thread in a 10/8/6 at 5' is a great length with 24" of 4x and then 12" of lighter tippet.