Ritchey Pro series is fine...but the WCS 4axis is their best and lightest all Al stem. FWIW Ritchey carbon matrix stems aren't as good...I have owned several of each...carbon delaminated around stem clamp bolts on one carbon Matrix stem...and Ritchey did warranty it but honestly, their carbon stems are more for aesthetics...not discernibly lighter or stiffer than their WCS 4 axis all Al stems.


A more value oriented stem and better than their Pro series is their Comp 4 axis....basic same design as their WCS 4 axis but a bit heavier.


Reading all you have written and done, I would say you have a good handle on your installation. Probably best to swap stems at this point.
Good luck