Interesting question from Shaddix and the answer is "it depends"!
We want to change the bikes heading as quickly as possible when we are doing rotation turns and the faster we go the slower this rate of change in the heading will be. There are a lot of variables that we need to take into account such as lean angle, steering angle and body position etc, so it's difficult to provide a clean answer.
If you watch any of the videos of the Japanese riders doing rotation turns, you will notice that the rear wheel is not travelling all that fast even though the front wheel might be whizzing round.
As with most Moto Gymkhana exercises the fun is all in the trying and spending some time working out the best ratio of speed aginst heading change will keep you occupied for hours! BTW, the optimum time for a 360 degree rotation is 2.5 seconds, so that should give you a bit of a clue.
Dedicated to the wonderful sport of Moto Gymkhana