Indeed, if you have the luxury of NWS then asymm braking isn't going to be a factor.
Your 'other factor' is what I meant when I talked about asymm mainwheel drag (perhaps I expressed it poorly). It certainly would be minimised by appropriate spoiler/aileron. You could (to some extent) steer the F4 on the runway using aerodynamics to load/drag up the appropriate main gear.
I'll give it a go some time when we have suitable crosswinds and I have a spoilered AC to fly :-) If you get there first, please let me know what happened!
Cheers,
MT