Yoda does not recommend the closed-closed variation for hitting. I have talked to him, and he will comment further in this thread.
Regarding my personal square-open combination, the TGM player can change any stroke component to create a different result. Because of my open stance (10-5-B), I automatically create a Delayed Pivot (10-12-C). In other words, I have created a restricted backstroke (relative to the Free Turn of 10-12-A) and a free follow-through.
It gives me a very robotic feel, as if my legs are stuck in concrete. I almost have a zero pivot feel.
Your preference for Square-Open has my attention, Ted. Personally, I've been migrating in the opposite direction toward Square-Closed. I'm looking forward to more comments from you and Yoda on this topic.
The Stance Line will affect only the degree of Pivot Motion during the Backstroke Turn or Follow-Through (10-12). It should never affect the Plane Line.