Oh my goodness... I can't beleive you got this many responses without the obvious answer:
It depends.
How much does your foot rotate as you go through your pedal stroke? Depending on your knee/hip/ankle alignment, your foot may tend to rotate to the inside or outside at different parts of the pedal stroke.
*Most* people will be fine with the grey cleats. No way to tell over the internet. Try it out. If it doesn't work (if you can't adjust the cleats to avoid bumping up against the edge of the float in both directions), get the red cleats.