You are definitely fighting the tensioner when putting the CAM gear back in place. I don't have experience with doing it this way. I have seen others do 4 cylinder Honda's in this manor. Are you only fighting the rear head exhaust CAM or another one? If another, you will want to get it in place first then do the rear exhaust. However if you don't have a way to leverage the tension, you might be better off pulling the cover.