Yes Grey is right that you stay really wide. I don't know if it is really cardinal sin if you are wide when you step with your punches, but one is for sure you over reach with the right and there is nothing left for the left. When you step and jab like this hold your head over the left leg and turn your shoulders. This will not only stop you from over reaching, but it will give you the distance for the left hand, more weight behind the punch and you will use the stretch reflex in your back.

Other question is how wide is wide and on which distance and hight level. What will be criteria?