Very good Kavik!
When he starts stacking with secure feet- that is when you work on lifting the paws to straighten- then he learns this is normal procedure.. Also After learning the lead- get a show lead ( different than his collar and leash) and take a few steps so he practices trotting along side with you- bring him around in front of you to stack- do not step in front of him yet- this will teach him to watch your feet- instead of keeping his head up.. Also- I bait my puppies after they look at you and stack, I say real low but happy " Okay".. then give the treat-.. The reason is most judges will say " Okay- one time around .." etc- and the dog will look right at the judge for one more impression before going... lol