Hi Luiz,
I recently watched the Australian Moth nationals. The two foilers present used foils constructed by Fastacraft (www.fastacraft.com) in Western Aus. They had bow mounted sensor arms, ala rave, operating trailing edge flaps on the main T foil via a specta loop. The Rudder T, had a flap controlled by twisting the tiller arm, as used on the I14s. This takes care of pitch angle, and allows the skipper to have control of takeoff and gybing. Lateral stability requires the same hiking and mainsheet/steering activity of non-foiler moths and dingies, though the foilers are actually a bit easier to keep upright.
The series was won by Rohan Veal on his foiler, who literally ran away and hid from the non-foiling competition upwind and down. He said it was about the same speed as a Tiapan 4.9 upwind and faster down which I can believe because he smoked past my little 14ft Alpha Omega Cat. Incidently, for those who have'nt seen them, the modern Skiff moths are only 11ft long, 13 inchs beam with 86 sqft of sail. In displacement mode, they still sail faster than many 16ft cats despite their waterline disadvantage. All skiff moths have T foil rudders which allow them to exceed their pitch pole induced hull speed limit, and also trim the hull to gain dynamic lift at speed.

Cheers

Simon