MfS
Your post raises a couple of questions:
Is there ever a determination of the effects of reduced friction on Vmcg? It seems like there might be based on the wet case.
Is there a determination of the effects of crosswind? I know it is not required by the AC, but is it done the OEM's engineering data?
Lastly, while 30' deviation from centerline is the standard, are there tests which address lesser deviations, that is higher speeds for Vef? Perhaps for narrow runways ops.
GF
Yes, I went over on number of questions, please forgive.