Dumb or not - I asked my Dyno operator the same question and his answer was "No,it does not make any difference, not the which gear is used either. Most commen is to use the 4th gear since you can get a fairly stable and long enough run but you would get the same result with other gear ratios". That was what he said and I tend to belive it.
Regards
Hasse

Hasse TBA -02 Pre-Fire Cardinal Red, Wiseco 904, Thunderbike pipes, Freak