Right hand hits from a right hand shooter are from, milking through the trigger stroke, pulling the weapon to the right. This condition has been rare. Hits in the bottom center are caused by closing the whole hand, not by using only the pressure of the thumb and forefinger. It is good to have a full size square target to reveal these hits. A good test to show the student that it is trigger control that is lacking, not something else, is to have them align the sights, then remove their finger from the trigger and you apply the pressure to fire the shot.
Shooting is a matter of waiting, let it happen.
This is different than the eyes off drill. Teach them to manage the slack in an auto pistol. If it is a 38 with little recoil this is not so important. The take up of pressure in the number four position of the presentation, is where the P7 is cocked. Afternoon spent on range work including fun house, and apitir .