...Now that you mention that the use of powder style floatant as being slower than Gink I may stop using floatants altogether. I'm obsessed with getting my dries to ride high on the small creeks where I am running dry/droppers. I like to ensure my fly can keep a 2.5-3.0mm beaded dropper afloat. A buddy of mine gets really irritated with the amount of floatant I use and says that "needs more floatant" is my tag line. Do you pretreat your dries before fishing? I know some people pretreat their dries with a hydrophobic coating. I have not experimented with that yet but may give it a go...
I wrote this short novel to offer a couple of tips and detail a few misconceptions regarding floatants:
1. One of the biggest misconceptions I see out there regarding floatants is they can be AS EFFECTIVE reapplied to flies that are still wet/damp.
2. The other misconception is that pure hydrophobic fumed silica (think Frog Fanny) is a desiccant meaning it will dry your fly as well as make it float.
3. Pre-treating flies with anything is worth the effort.
4. Combination powdered floatants containing a desiccant (think silica gel crystals) and hydrophobic fumed silica are the answer to #1.
First of all, a CLEAN & DRY floating fly treated with anything will float better than a slightly damp fly that you re-treat, UNLESS you effective dry it with something FIRST. Reapplying Frog Fanny isn't the way to make that happen. Reapplying Frog Fanny to a damp or wet fly will also cause the fine powder to become embedded in the dubbing which in effect makes the fly heavier and shortens the benefit from application.
The same thing goes for silicone based products applied to a damp fly ESPECIALLY if they are not liquefied but congealed at room or stream temperatures.
For at least 500 years I have using
Cortland Dry Ur Fly crystals to dry off flies I have been fishing BEFORE I retreat them with any type of floatant. Dry Ur Fly is super fine silica gel crystals that make short work of drying off your fly because the crystals are so fine they really get into the materials, something the larger crystals you find in combination powdered floatants or even the packets found in electronics can't accomplish.
I'm not positive Cortland still makes Dry Ur Fly but it can be found in fly shops because I'm about the only one still buying the stuff. 
A worthy substitute is very fine silica gel crystals used for drying flowers.
About 5 years or so ago I added a quick squeeze between an
Amadou patch to the "drying" steps. So the process is; Amadou squeeze, pop the fly STILL attached to the tippet in the Dry Ur Fly crystals, shake, remove fly, flick off the excess crystals and retreat with the floatant of your choice.
It sounds like a pain in the arse and it is, but it only takes a few seconds and the "dried" fly is about as dry as it was when you first took it out of the fly box. If you dry first, you get WAY more bang for your buck when you redress it versus not effectively drying. In other words,
you will use less floatant and dress less...
I should also mention that I don't find it necessary to do the drying and redressing thing after each fish, only after several and I attribute that to not having moisture or embedded stuff in the flies BEFORE I redress them.
The other thing I am adamant about is when a fly gets slimed up or just doesn't seem to float as long, I cut it off and tie on a fresh one. Years ago I used solvent based floatants that were SUPPOSED to clean off the slime but if you don't allow those liquid floatants to completely evaporate before the next cast, even the floating benefit is short lived.
Paste or silicone based floatants repel water great, however they eventually load up dubbing and other materials on your fly with silicone making the flies slightly heavier so that they sink faster despite being treated. For that reason I have completely abandoned the use of liquid or gel floatants and just use hydrophobic fumed silica applied to a clean dry fly.
Even a soaked retired fly is like new the next fishing trip if is hasn't been gunked up with silicone.
In regards to pre-treating flies, it definitely helps for awhile if you have the time and inclination. However in my experience once the fly got effectively soaked the first time it didn't respond to floating well again if I just dried it out in the field or floated any longer if dried and redressed with floatant or Frog Fanny than a fly NOT pre-treated. For that reason, I don't bother any longer.
The other thing I should mention that can help drown a floating fly is a leader sinking badly or getting pulled under by micro currents. For that reason when I want the maximum amount of float when I'm not trying to fool some Mensa trout, I will grease my leader all the way up to the fly. In my experience, 99% the fish could care less...
Hopefully some of this drivel my benefit someone...
