Practicing Stage One on the range is a very dull and expensive way to get the job done. But if you have no alternative, visualize a chipping green and a near target, otherwise your Stroke will be too long, and you will exceed the Basic Motion's boundary.
If the range isn't too busy, dump your balls out and chip to the range basket. Pick up 'em up . . . chip 'em again and again and again.
Depending on their pricing structure indoor golf domes are great for this reason alone. There is a dome near me where they have a short game area which you can use for FREE. Unlimited balls. Then you can go to a hitting station where you're only charged by the amount of time you spend in the station. Again, unlimited balls. Besides, it's only 90 yards to the other side of the dome. I find hitting drivers in domes a waste of time.
How far should the follow through go during 12-5-2 Acquired Motion? I normally practice it with my arms going to Both Arms Straight. I do it both with and without a finish swivel but not sure this is correct. When I add the finish swivel, I get a bit higher ball flight and a bit more carry.
Homer references 6-4-A for the follow-through with 12-5-2 and I believe Both Arms Straight is the correct way to interpert this reference.
If you haven't done so lately, take a long hard look at 12-5-0, 12-5-1, 12-5-2, and 12-5-3.
I start every range session progressing through this section and it really helps to get everything going in the right direction.
Trig
I do the same since i have uploaded "A Lesson with Yoda - Collin Neeman"
video (specially chapter 1,2 and 3)
The video incited me to reread 12-5 chapters.
Right from this time ALL my practice sessions, start as yours and I can attest that you are totally right.
These are not only the best foudations for a solid golf swing, but my short game have really improved +++.
I stil have some problem with 12_5_3 (Pivot , Swivel...). But maybe this will be the subject of a futur post.
Thanks
Pm