I've found that they don't usually do well with floatant applied directly to the fly; the hackle sticks together and you loose that nice uniform look. If I'm going to use it dry, then I actually grease the tippet just in front of the fly to keep it from sinking. It works really well that way. Some of the dry silicone powders or sprays might work pretty well applied to the fly. It will float quite well without any floatant if you can make a good delicate landing on the water. They fly is so light it rides nicely on the surface film. Keep in mind too, that if you're using floro, it's going to pull the fly down, so you will need to grease the tippet.

TT.