Hi, use to have 30's on my diablo. No manual but I have many years experience with them . Air pressure is a trial and error effort, oil viscosity also plays a big part with these forks. Start with the oil, i used a heavy weight oil due to the fact that I use to throw the jav & disc for hampshire. I set the pressure to give maxium travel without bottoming out . Once you have the right combination of air and oil they ride like a dream.