A great morning read Emma! Lots of good advice in there for all women (and the men interested in having better sex with them). A few thoughts in no particular order:

1. That Mr. Austin sounds like a wonderful inventive fellow. I reckon you should keep him.
2. All of your observations ring true to my experiences with the lovely hub of female pleasure and sensitivity. I would add that the corresponding soft ridge of flesh on the front and under the head of the penis behaves similarly with regard to sensitivity/desensitivity for many men.
3. The widely accepted view is that the clitoral structure extends far beyond just the glans/head of it, which may help inform the results you are getting from all the nearby bits. In Dr. Ian Kerner’s seminal “She Comes First” he even goes so far as to say the G-spot is the backside of the clitoral structure, a view I share.

Keep up the great work!