Re: distance varies with excitement level.

It looks like you have identified exactly what you are looking for. I don't think I can add anything that I've haven't already mentioned in several posts.
But reviewing your ideas:
Backing off to 2 to 3 times a week might do wonders. You may get many of your feeling back where you say it's rather numb. The Kegals ought to help your ejaculation muscle.

There is also (I think I mentioned this) Cobra enhancer which has natural herbs and is very mild. Some guys swear by this to help them rev up their sex life. I believe that would help a woman too ( not that your wife needs it) Many of the ingredients help with desire, blood flow, sensation etc. I think it helps a little and it's CHEAP and totally natural herbs used by Chinese for centuries to improve their sex life.

HO HO HO Merry Xmas