I did some drag testing with a friend and found that hands on the hoods/Sphinx position was more aero for me than the faux tt position and I a bit more efficient/more controlled. For my friend he had roughly the same drag in both, but rides the hoods position because its more controlled for him as well. Unless someone changes their stem dramatically to allow for the forearms to rest comfortably and hold onto something it seems pointless to pursue this position.
What I have found works the best as a compromise (but can make things awkward otherwise) is this:
-Run a bar that is 1-2 sizes wider than what you normally would run
-Run a stem stack that is 1-2cm lower than normal
-Run a stem that is 1cm shorter than normal
-Angle your bar so that the the tops and the hoods have a flat transition
-Rotate your bars upwards so that the tops/hoods are in line with the stem. On a normal road bike with a -6 stem this means they are on the same incline as the stem. This is why you run a lower/shorter stem. Rotating the bars increases the reach and the stack.
-Cant your levers inwards quite a bit probably .5-1cm each side. This will allow you to rest your wrists on the tops of the bars and lightly grab onto the hoods with a "pistol grip".
You can then rest your forearms on the flats of the tops and put your hands just inside of you levers. You will have much greater stability putting your weight just behind your wrists and the same drag.
A good picture of this and where I got the idea from is Fabian in the 2010 Tour of Flanders. A little birdie and Specialized told me that Cancellara actually tested this in the wind tunnel and is one of the few riders to still run wide bars to this day basically so that he can use this position. I've tried it personally and like anything you adapt to it, but it does make out of the saddle climbing feel a bit awkward at first.http://s3-eu-west-1.amazonaws.com/inspi ... LARA_1.jpg
Don't take me too seriously. GramzStrava