I have a hydraulic top link which is about the most awesome accessory a 3pt can have for changing the angle of attack on 3pt attachments. A hydraulic top link would also solve your attaching hassle.
My neighbor had the same problem but without the quick hitch. The top point on the mower pivoted back and needs to go foreword, yours is leaning back. It should go straight up. You may have to loosen some bolts to do it. Good luck.
The black link on the bush hog is designed to move around. It's currently rotated to far back. Push the top of the bush hog 3 point attachment towards the tractor. The black link should be more parred to the ground I think. Not so vertical. Then the top of your quick hitch will reach