Hi Fran. I understand your position on this and have read extensively about what happens during the pendulum stroke. I even found a mistake (typo most likely) in Dr. Dave's formula describing the arc of the tip. My conclusion from the math and from looking at it at the pool table is that the tip is horizontal for a good two inches before and two inches after contact, at least for how I hold the cue.
I played my whole life with dropping the elbow and found the fixed one to give me better results. However, I think elbow fixed or not is just a means to an end. If you can deliver the cue straight with dropping the elbow then fine, but it works for me the other way. Maybe after awhile I won't need to fix the elbow anymore and dropping it will work fine, too. Not to shock you (lol) but I get better still results by pausing at the back of the stroke. The pause allows me to relax the arm muscles completely that I can't without the pause, and it even gives me a split second to confirm the aim. I get fantastic results like that, and it was you who originally taught me the importance of the transition.
Edit: I should be clear that I have technically not experimented with dropping the elbow while cueing straight since I went to the fixed elbow. It's just how I played for a long time while trying to deliver the cue and things got immediately better when I switched over to the fixed elbow.