the 'correct' amount of ailerons would be just sufficient to offset the rudder input!
Don't agree with this at all. There are 2 factors affecting you on a crosswind take-off:
1- Lifting effect of the upwind wing
2- Weathercocking into wind effect of the side force on the fin.
Both quite independant. Rudder does not stop wing lifting.
You counter with:
1- into wind aileron
2- side force with rudder downwind
So you don't end up wrestling with controls whilst wheels are on the ground, I think you are best just leaving aileron fixed at your estmated setting, and keep tracking down the runway centreline with rudder. Whilst you are doing that, just feel for the upwind wing lifting, and hold it down with more aileron if need be. The lifting effect will probably reach its peak near rotate. When you lift off, you will instantaneously be in yaw in the air. You had better have your aileron on then, because that is when the wing will lift- and that is just when people tend to freak that they are airborne with all this aileron on! So off comes the aileron, the aeroplane tips downwind, then on comes up to double the aileron to get tyhe downwind wing back up. I see it all the time, then tell the copilot how much aileron he had to put on because he didn't listen to daddy!
Olendirk- try it, and report back. If you take that aileron off at take-off, try and see how much you then have to put on to level the wings. If it is not double what you would have had on the roll, I'd be surprised.
I think in threads like this, one should say what experience one has. 34 years on jets, nearly 20,000 hours. 18 years 747, 10 years 737, 6 years VC10.
(Heavens- we haven't even got into crosswind landings yet!)