Whatever pressure you use you set that pressure just before going to the track for your first session. Immediately you come in you check the pressure. About 2-3 minutes before you go to the pre-grid for your next session you check tire pressure and set it at your chosen one. Usually you'll have to let a pound or two out. Immediately you come in you take pressure again. You do this each time. Some days you'll let air out every time. It will depend sometimes on weather.
For me, taking the pressure when you come off the track will help you read the track, weather, tire, etc.. It will tell you if you are working the front or rear or are using them together. It's hard to overwork the rear on my 550 but my GS 1000 will really heat up and bump rear pressure up. The important pressure is the one before you go to pre-grid. You are going to have one lap and then the green flag, by my experience.