What track usage should I practice at?

Title speaks for itself, me and my buddies have been racing the FIA F4 series. We are all new to the game so outside of F1 tracks we are completely new to the tracks. Well watch track guides to start a basis on braking points and things but in the videos they’ll practice on ab 44-50% track usage. The thing is once the week starts for the track well easily break our best lap time within one or two laps, while constantly putting purple sectors down on our laps. What percentage would be good for practicing more likely race conditions?