If you have warmers, a well setup suspension, run proper pressures, and decent track temps, the GPAs will last you at your pace.
The issue is, if any of the for mentioned are not ideal, they will not last. I coached all year on one set of GPAs but took good care of them.
A good starting point is 32 front and 23 rear hot on the warmers. Adjust depending on temperatures.
If you don't have experience reading your tires and monitoring pressures just before and immediately after leaving the track, go for the Q3s.
With the Q3s, you don't have to mess with warmers and they will easily run your pace. Not sure of a starting pressure though. A few of the coaches run Q3s and will have better experience with them than I.
Hope to see you at the track!