Uh...guys. The effect of raising the speedbrakes is that of changing your Vmcg, due to the yaw. The drag will be negligible.
I'm not talking about a 5 knot x-wind T/O, but a procedure that will keep you safe when taking off in max x-wind, V1 close to Vmcg, and then add an eng fail on top (critical engine, that is).
In our FCTM it says exactly that. Use a maximum of 6' aileron deflection during ground roll. Keep wings level during rotation.