Please take a moment to critique these two vids if you have a second.
Essentially my drill uses a metronome (have always struggled with tempo) with a right forearm takeaway, over exaggerated hip slide, followed by a hip turn focusing on getting the shoulder as deep down plane as I can.
My biggest faults have always been over acceleration, inside plane takeaway both of which has lead to shoulder spin out in the downswing.
I'm trying to drill out all 3 of those problems at once.