Sneak Peek at the Doggon Wheels

I'm still figuring it out and need to get some advice from the Doggon people, so it's not perfectly fitted yet.










Specifications:
Tires in bottom, farthest back holes.
Vertical tubing at shortest height.
Rear harness at shortest length.
Horizontal tubing at longest length.

Questions for Doggon:

1) The horizontal frame is not above back but rather level with back. But if height increased, cart will tip forward.

2) Cart leans forward slightly.

3) Is back strap supposed to sit on shoulders or lay just behind shoulders?

4) Horizontal tubing at already at longest length. Will not be able to increase length any further.

5) There is slight swaying of the cart when Popeye walks. Most likely if he were to run, swaying would be even more pronounced. Is this normal?

6) Is front harness adjusted properly?

7) Leg openings in rear harness a lot wider than thighs.

8) Shoulder strap seems tight, especially when he bends down.

9) He sometimes lifts his butt up from the rear harness. Any way to force him to remain seated?