Great job on that harrow!
The information on the 673 made me feel better about my recent purchase. I threw it on the bill when I bought my 5045D the other day. It was REALLY EXPEN$IVE! I considered it an extravegance, but it was for my wife to make her new garden spot with. I've been promising her a new garden location for a couple of years and was delinquent in fulfilling the promise. I used to garden with a mold board, disk, cultivator and bedder. All but the mold board belonged to an elderly neighbor and I plowed his garden in return for the use of the stuff. He passed away and the stuff disappeared. I think his kids from the city sold it.
After I bought the 673, I started having buyers remorse because I saw so many cheapies for so much less money. After reading your description of it, I now feel justified with the purchase. I'm still clearing the fence row on both sides of her new garden, but should be tearing things up with it in a few months. I'm looking forward to using it.