[JerryHawk250]

I had a busy weekend so just reading this tread. I don't know if it's the camera angle or not but there isn't much clearance for the chain with a 17 tooth sprocket. It would take much to cause some major damage to the housing with the chain jumping tooth. Hoping it's just an optical illusion. if not I would drop to a 16 tooth.
Best way to adjust the chain is to get a ratchet strap and attach to the swing arm and rack at the rear and ratchet it down until you find were the chain will be at it's tightest position. Adjust the play in the chain at this point. Once you remove the ratchet strap you will know exactly how much play there should be in the chain without a load on it. The second to last video looked to be about the right amount of play at the tightest position.