This is the beauty of the Pat's system. If you can get the Pat's hooks lined up under the two implement's lift pins then raising the tractor's lift arms will engage one hook and then the other - sort of self-leveling. The top link is easy after that.
It does take a bit of practice and the hooks have to be at the right width to make everything go smoothly.
You can make spacers for each piece of similar equipment out of re-bar - just bend the tips about 2" from the end. Or, if you weld, just weld a 2" piece on each end at the right spot. Slip them in the spacer holes on the Pat's before climbing on the tractor and you are good to go.
My storage area is gravel and not level also. Pat's EC makes it a breeze to hook up.