Scott,
Why is grip ahead of perpendicular a bad thing? That is the way many older professionals like Mosconi shot. I like the feel of that myself because when drawing back the cue doesn't bind between the fingers and the web of the hand. Correct me if I'm wrong, but I think Efren is also slightly forward of perpendicular.
Now, the single biggest thing I saw which would help you is your approach. There is a video at the top of the video section here which is awsome regarding this subject. I can post a link later, or PM me if you need.
I also noticed that sometimes going through the cueball, you were driving with your upper arm. Bustamante seems to do this too, but it seems to make most people inconsistent.
IMO, head height over the cue is simply: Up - Object ball aiming focused Down - Cue ball aiming focused. Not an issue, just be consistent.
At times your cue could be more level, but maybe I am not seeing everything correct.
The video lacked much footage of your stroke arm side. It was only shown once or twice. Ideally, it would be best to show like 30 side pocket to side pocket shots with a view of your stroke arm side. Maybe 10 closed bridge, 10 open bridge, and 10 off the rail(cue on rail) bridge.
Good luck and enjoy the game. BTW. . .I love the idea of a table in the garage! You are my hero. I could put a 4.5 x 9 in there.