This was the system I bought and used for over a year. I was able to make impressive gains and it was a real turn on when you come out of the tube so large. Make sure you start at a real low pressure and short time and slowly over several days and weeks, build up the pressure and time in the tube. I would say 5-6 would be the max pressure you will ever need, but of course, you, like me, will experiment higher. I would really start to pump up, when I finally got my time in the tube up to 30 minutes and longer.
Newbie mistakes are broken blood vessels, blue cock, and water blisters on the head.
For all the pumping I did, and for as large as I got, as big as 7.5x7.0, I found that for me, I could not make the gains permanent. Also tried pump then jelq routines, and still the gains would not last. So now I am back to the basics. Hand stretching and jelqing, and I am making great progress with lasting results.
Good luck with your experiences.