Looks great. I agree that the weight would be more evenly distributed if the wheels were more centered, however, with this design, I believe he is correct that they need to be where they are, as you can see he has the floor of the coop part off the ground, which is why the wheels doen't hold the whole pen bottom edges off the ground, so predators can't get in. If the wheels were moved back, they would hold his frame of the pen off the ground.
Looking forward to pictures. Good Luck.
Looking forward to pictures. Good Luck.