I've tried both recently, and the game has suffered from it big time. Whether it will pay off in the long run remains to be seen. I think the two extremes are very difficult to master at the same time.
The hinge action and swivel action is very different with low hands (elbow plane) and high hands (TSP) All things equal, it is much easier to close the club face when the shoulders are turning on a high plane and the hands are down low.
Further, the larger angle between the right hand and the club shaft at impact requires less closing of the club face and also a more gradual one than when the left hand is close to uncocked at impact. If your left hand is fully uncocked at impact you need a quick 180 rotation through the ball. If your left hand is vertical at impact you dont' need any additional forearm rotation through impact at all.
So you need to do a lot of things different to maintain club face control on one if you're used to the other.
Different rhythm,
Different hinge action,
Different heel toe balance in the stance. More towards the heels from EP.
Different push-pull balance through the ball. More pull from EP.
Different hip tilt. Less from EP.
Different pivot-arms rhythm. More turn through before impact from EP.
Different use of lower body.
Different force center. The swing force center will be lower in the spine on EP.
Different footwork.
If one of the planes work well , the other will at best be mediocre. Unless you're a true master, I guess.
Coming from low hands I can subscribe to what Ted says about the fulcrum. To some extent the tendency will be there with TSP as well, but more so on the elbow plane. Shanks has never been a pattern-like problem to me, but divots towards the deep side that steals distance on bad days has always been a signature in my game.
Short game and tight lies have not been more of a problem to me than other single handicappers, perhaps less. I used to have a pretty good semi flop from the hard pan, just sweeping the LW under the ball on a very shallow angle, with a frozen accumulator #4. Probably on the hands plane. I haven't needed that shot for quite some time so I don't know whether it still works. One of the advantages with low hands (and a flat swing) on the short game is that you can do a lot of accumulator #3 on a short path to get a good flowing motion on short strokes. And the shallow angle helps a lot on tight lies if you know how to use it. Also, you can be a lot less armsy and handsy through the ball. Slow and firm is always good in my book. But slow & firm requires a different pattern on EP than on TSP.
Ever since I tried to adopt to TSP and stock TGM alignments early this year my game has been in a mess. Obviously, I've been playing with conflicting alignments. And they are much bigger than the conflicts between hitting and swinging for sure.
Eventually I decided to forget about all alignments and just focus on what happens around impact. The idea was to find back to the old self. But that seems to be gone by now. Hopefully to be replaced by something better.
My average score half a year ago was in the high 80's. Now it's at least 5 strokes better. For the last two months the consistency has gradually improved, but the feel system and the alignments must be in a state of transition. It hardly ever feels like the perfect shot. The best shots are 90% solid.
When I hit good shots on TSP a few months ago, I had to stall the shoulders and let the hands pass the pivot through impact. Some of the shots were excellent, but it didn't feel right. The feet wasn't into it. Because I was still using a lot of the EP stuff I guess. Eventually I stopped thinking about EP and TSP, and just tried to get back to solid ball contact and staying connected through impact.
Two days ago I shot in the 70's for the first time in a year. Shot a 37 on front nine with a trople bogey. That was a long wait for an OK round. I observed that I was flirting with the TSP now. I had a visual of the club face closing during the impact interval. My old EP image is that of keeping the club face open until last instance - a reverse swivel in the down stroke at it's best. Swinging the heel of the club so to speak.
Swingin on TSP, my weight balance under the feet has moved slightly towards the toes. On EP I need to be swinging basically from the heels, the shoulder turn is directed on a plane above and parallell to the elbow plane. Hula-hula and right hand brings the hands down low. Impact happened more towards the left side of the body than on EP. The force center in the pivot is higher up in the core. And the direction of forces is more downwards at impact versus more outwards from EP. And then, a clear feeling of clubhead closure through impact.
I'm not dismissing neither low hands or TSP as inapropriate. Far from it. Everything is very different. So different that playing with both can get you into trouble.
But I am beginning to realize how different the two are. I can now address the ball from impact fix, on TSP "knowing" that I can drive hard with my pivot all the way through the ball. I've never been able to do that before. But I really need to anticipate a rapid (for me anyway) clubhead closing at impact to pull it off from the TSP.
I'll keep focusing on solid ball contact and good pivot action through impact. Then I'll see what plane I end up with. Or perhaps I get to the next level and can produce both planes at will.
I had an 8 iron that flew about 30 yards too long in my 79 round. A hot bullet that took a bounce off the back of the green and proceeded to a spot from where it was almost impossible to save par. I've hit solid 5 irons shorter than that! It's a new miss for me. One of the things I like when I swing on the elbow plane is that the different clubs have a very reliable max distance, that hook misses are most of the time just a tad long. Distance misses are basically moderately short instead of 30 yards long. Which is easier to recover from on most courses.
On the 18th I had a big slice off the tee. It is not the first time, but this time it flew 20-30 yards longer than usually, carried a pampus that would othervice given me another triple bogey, and I had a semi rough lie 165 yards out. A 7 iron to pin high and two putted for par and I posted a 79 on a very penalizing golf course
So the new pattern worked against me on one hole and helped me on another.