To the original question, if your dog moves with your leg movement, either stand while running if it is an option or move your legs while on the bucket.
Nate great accomplishments with your dog sounds like you have a very well balanced animal. I haven't ran the Grand but have trained with many that have had success. Of course the dog has to mark the birds, but holding the dog together for several series of shooting poppers over them while keeping their butt on the ground is the key to success. There are many great dogs out there but not all are geared to play the Grand, just the same that not all Grand dogs will become all age qualified. They all are different. From the truck to the holding blind to the line, everything nice and slow. Maintain high standards all around. Use lots of holding blinds, making the dog wait his turn with excitement going in the field. Be the first one in the holding blind and the last to run. Put birds absolutely where the dogs don't want to go. Use wingers with nice arcs on throws, no noise in the field. Start off with singles/multiple stations no gun at the line just sit on the bucket, keep the dogs butt on the ground, and let him find his mark. Later up the standard by shooting a 20 gauge at the line with singles not pointing the gun at the birds just yet, we are still focused on keeping his butt on the ground. Put the bird where he doesn't want to go, run single marks that will build off of each other. Tough control blinds, through old falls and under arcs.
Good training brother
Sorry left one very important thing out. Use natural brush, trees, or clumps as your winger hides. Don't expose gun stations. A winger hide is still very much exposed. Winger hides out in the open are great for weekend HRCH and MH tests but not the Grand.
Y'all need to stop putting price tags on those free jackets, My wife could read this!!
I would prepare for the Grand by doing nothing but OB work in the morning and evening for a couple of weeks about three months before the Grand. Tighten that obedience up drum tight well in advance. Then, bring it to the field, upholding that elevated OB standard.
Your standards have to (obviously) elevate on all fronts. As I said, about 3 months out, I ran lots of singles and doubles to firm up marking/lining and ran lots of factorless cold blinds so I made sure my casting was rock solid. Then, about a 2 months out, start elevating the factors in your set-ups. Almost like drills before taking it to scrimmage.
Hope that I'm making sense....
The individual that was in charge of acquiring, ordering, and approving those jackets decided on that particular style. My 1000 pt jacket has that lovely feature...My 1500 pt jacket does not. I do not think the new ones have "backwards" zippers as HRC has recently changed vendors.