I think you might find your instructor won't want you to H/T until you can consistently do it without missing. The purpose of H/T shifting is to get you into a lower gear as you go into a corner without upsetting the balance of the car. If you go into a corner fast and blow a H/T down shift you could be in real trouble. I H/T all the time on the street just to keep me smooth for the track. It becomes second nature after awhile. One added benefit of H/T all the time is less wear on your clutch.