i shift at 3k - 3500...it's smooth and no "jerk"
4k also is good
i just hate it when on the stop sign, unlike autos, i have to downshift to 1st if i want to take off smoothly/quickly
if i sta on 2nd and do an american stop, the car takes a while to climb the rpm, and i think it's bad for the engine. so does going to 1st while the car is still moving (slowly to a stop that is)
then again, i also rev match sometimes