Re: Repetitions scheme
Our normal practice is for the senior student to perform the demonstrated technique first, twice on each side and then switch to the junior student and continue doing four and switch until the instructor stops the process. If I am senior, I prefer to do the technique once on each side to ensure the junior student gets a chance since sometimes things move pretty quickly.
After class, all that stuff goes out the window and perhaps Nage may do the technique on his weakest side ten or fifteen times in a row or something like that. The bottom line there is getting things correctly and doing lots of repetitions.