Hi, Starlette and Julie!
I get to puppy sit for a friend's Shih Tzu from time to time, and just love her so much. Shih Tzu are great dogs, and Julie is such a cutie.
My Yorkies get along great with my friend's Shih Tzu, and they do have some similarities. I cannot imagine you would be unwelcome here on YT.
You said you had difficulty finding a forum specifically for the Shih Tzu breed and I was wondering if you happened to discover this one:
shihtzuchattertwo.sunlitesplace.com/