The major standards are a bit confusing honestly. Fair trade provides a baseline above the commodities rates, but they don't ensure that the farmer is getting the most for their product. Furthermore, the farm has to be able to be certified for conforming to certain environmental conditions prior to being certified. Many coffee farmers are so far off the beaten path that they simply cannot afford to be certified. I believe that conscientious importers provide a far better compensation to the farmer.
It looks like Fair Trade assures something between 15 and 35 cents above commodities rates. This is far below what a roaster will pay for specialty grade coffee. While fair trade is a good baseline, if you purchase specialty coffee, you are most likely buying coffee that was purchased for significantly better than fair trade rates. To give you an idea.. I pulled up a random invoice I had in my inbox and it was $1.70 above commodities rate. Furthermore, importers provide on the ground support to farmers in the form of varietal education and recommendations, disease prevention, washing technique improvements, all of which net the farmer tangible benefits because their coffee will improve in quality, and thus, sell for more.
So.. if you are looking for good ethical compensation for farmers, I would say look for local specialty roasteries. These roasteries are purchasing high quality coffee from a high quality importer which means that there are people on the ground helping farmers achieve better quality, and thus better compensation.
The link below is a pretty interesting article from a greens buyer I am thinking about working with. I found it a very interesting read that gave some insight into what importers actually do, and highlights why a lot of coffee farms are not certified..
40 hours in the life of a greens buyer
I know this explanation doesn't directly answer your question, but hopefully it sheds some light on the behind the scenes of how coffee buying works. Fair Trade, Organic, Rainforest Alliance are all great programs, but they can also exclude a lot of hard working farmers, that produce fantastic products, and are very conscientious of the environment etc.
One last bit of food for thought.. My roastery cannot advertise our product as Organic because our kitchen is not certified Organic (I've been officially open only for a few months, after a years worth of building my business and haven't been able to get certification lined up yet). Despite this, half of my products are certified Organic. Looking at it from the business perspective, I would love to advertise my product as Organic, but just haven't been able to navigate the red tape, and I am sure there are other small businesses that are in the same boat.