I admire and applaud your courage to undertake this project. It's no small thing to abandon something with which you've come so familiar and chart a different course. I know because similarly, I rebuilt my swing last winter (also in the comfort and convenience of a cold, unfinished space). In the course of hitting the first few hundred balls off a range mat, I developed severe acute medial- and lateral epicondylitis (tendonitis) in my right arm. In fact, the whole reason I decided to rebuild my swing was because I had been experiencing reoccurring tendonitis over the years which ultimately forced me to give up the game for several years and take up something far more punishing -- competitive cycling.
Those of you who know about golfer's elbow and tennis elbow would know that you'd have to have a pretty bad swing to develop both kinds of epicondylitis in the same arm, and yet I played in the low single digits even with some level of pain. And being young, I never bothered to rectify the problem until the years took their toll.
During my golf renaissance, the most important thing I learned about epicondylitis is that it is caused by a strenuous repetitive wrist action--an incorrect golfing wrist action--and not necessarily some poor mechanics of the elbow. And the ill effects of the wrist action is compounded by the club's violent impact with the ground.
I mention this because I had to wince while watching you strike that artificial mat laying on a concrete floor--a setup very similar to the one I had originally devised. And I can only imagine what fate is in store for your epicondyles. So I just wanted to share what I did to avoid aggravating my tendonitis prone elbow as I rebuilt my swing avoid redeveloping the condition in the future.
First I replaced the typical practice mat with a Fairway Pro divot simulator, and placed it on a rubber mats commonly used with a indoor stationary trainer to give the Fairway Pro some traction as well as absorb some of the impact. The other thing I did was to begin practicing with a Tour Striker training iron. This had a twofold benefit. First, as a training device, it helped me improve my swing mechanics and thereby eliminated one of my swing tendencies that contributed to my injury. Second, since the blade of the Tour Striker doesn't have a leading edge, it doesn't make contact as violently as a normal iron.
Between using these two tools, I was able to hit balls for countless hours all winter with minimal aggravation until my tendonitis eventually cleared up completely. And after rebuilding my swing, I didn't have a recurrence all season. And playing pain free, I was able to return to the low single digits.
This off-season I hope to add a Net Return so I don't have to waste time chasing after balls.
Anyway, good luck with your project. Let us all know how it goes. Hogan's swing is a beautiful one to emulate. And a daunting one at that.