Monocock, What type of mower do you use?
I just use a 7' grass topper behind our old MF135 with well worn tyres, set to its lowest, but thats still a bit over 2".
I take your point about keeping the grass short and cut when dry so that you avoid clumps when cutting.
I find that it makes very little difference to the take off run in the Rallye unless the grass is over 5-6".