I think that this is one of very good questions and the answer for that is not so easy, because it depends on many factors.
For example my personal record with forex scalping strategy is more than 500 trades/scalps per day. (I don’t remember exactly, may be i will try to find it later)
But at average i make around 30 – 50 trades/scalps per trading session.
It depends on forex market trading conditions, because time to time i have great trading day, when all of my trades/scalps ends with profit and these days i really like to risk little be more, because i allready have a profit plus i risk partly my money, but mostly profit money, which can leads to much more higher profit and many forex scalps.
What i really like to do is cost average effect of several opened positions, because i don’t scalp forex market by just one trade, i open at one time 10 – 150 trades/scalps with different size and my focus is on average prices of all traded volume. Most of the time i focused on one direction with partial forex scalping hedging, when i have positions/scalps on both sides.