Just read your thread Josh, i had a lesson with very similar probs on retaining spine angle.
First move was weight on my toes, then at impact i stood up. Hitting it right with a active right had getting it back on line.
Pro gave me a drill which really helps.
Get a elastic cord, wrap it round your waste cross ends over and hold each end, with a little tension. Have arms straight with elbows in, feeling connection at arm pits.
How look in mirrow as you turn back and forward keeping same spine angle thru the sequence, most important at impact.
Described the hub of the swing been angle formed by T line down back and thru waist, if it moves it gets a lot harder to compensate.
Hope this makes sense.
Did you have a leaderboard ? what did you think of it?