I often find myself in quite a pickle with gusty crosswinds. I correct very well in most maneuvers, but the maneuvers that require a stall (stall turn, spin, etc) are giving me trouble. No matter what I do, when my power and airspeed are low/stalled my airplane blows with the wind like a kite. It is especially pronounced when the stalled maneuver leaves the plane of the wings perpendicular to the wind direction. How do you masters and FAI guys keep this from happening? Can you do anything besides correct before and after the stalled portion of the maneuver?

Not much ! . . When the airplane is in the stalled condition it is not flying, so is at the mercy of the conditions. Relevent sections of the FAI-F3A rules are below . .

JB

5B.7.4. STALL-TURNS
. . . . Drift of the model aircraft during the stalled condition must be ignored, provided the model aircraft does not drift outside the aerobatic zone.

5B.7.6. SPINS
. . . . In order to spin, the model aircraft must be stalled.
. . . . Drift of the model aircraft from the flight path at this point should not be downgraded, since it is in a near-stalled condition. However, severe yawing or weathercocking during the near stalled condition, should be downgraded by 1 point/15 degrees.

5B.8. WIND CORRECTION
All manoeuvres are required to be wind corrected in such a way that the shape of the manoeuvre as described in Annex 5A. is preserved in the model aircraft's flight path. The exceptions to this grading criterion are in the stall turns, and spins, where the model aircraft is in a stalled condition.

if you are flying in a strong head wind you might want to point the nose of the airplane into the wind a couple of degrees. (under pull ) this will help the plane fight the wind from pushing the plane back. and what I do when i am about to stall the plane and perform the stall turn is I pull to vertical completely and perform the stall. then on the way down I will tuck the nose against the wind to keep it from cramping me at the center of the box

I hope this made sense to you and hope it helps. lol