Drilled holes in two 3" diameter, 5ft PVC pipes & attached it to his harness & breastcollar so he felt the pull against his chest, no problems. Then added 2 rider mower tires & he drug them at a walk & trot, zero issue! Hmm, will try to make an axle to roll 4 old mower tires I have laying around. Then switch to the old truck tire I have. 12" would be the highest I can make the poles at the rear. I think his issue isn't anything related to poles, dragging stuff, being between poles or w/e. I think his issue is my fault. I was at his side leading him with one arm out and trying to move the cart along with him with my other hand. So it's my confusing body language that I believe is making him swing his butt away. I will attempt to get DH to help on a dry day with him leading & me maneuvering the cart. If nothing goes haywire, I will hook him up and see how he pulls as I lead him. =) Exciting!