4 straight up is a good number, the progressions can vary, it has to stand some total mad runs, like no hits for more than 140 spins. I have used casinos which allow bets from 1 to 20000 on straight ups.
The most aggressive is add one each spins, remove 35 on a hit.
The most Conservative add one on a hit.
I use sometimes more numbers, in some cases start witch 35 numbers.
The progressions can be individual, on each numbers, we stop on a decent plus.
There are some of my sessions in my threads here.
The bankroll need to be 1000:s and a session can in some cases be very long