Just thought I'd report back that my chafing problem has been resolved through, of all things, a refitting of my bike!

I had followed most of the tips already - waxing, applying various things, didn't try the real chamois pad because sounded too gory of a material. I still had problems until I had my bike refit. I did that because my knee really bothered me on a century ride, so I figured something was "off".

I had never thought about it, but my left knee kind of always rubbed the top tube, and during the refitting we raised my seat, angled it, adjusted my cleats, raised my handlebars - just about everything was changed. It seems over time your strength and positioning can change, and the fit needs to be rechecked.

Voila, no more chafing, not even in the least. Yay.