2nd try yielded very successful bao (steamed buns)!
I followed whattocooktoday's recipe , which has lots of helpful explanations of rationale and alternatives. I used corn starch (didn't have wheat starch or pastry flour on hand) and it worked just fine, the steamed bao are very light and delicate. I also used active (not instant) yeast; it didn't bubble much when using cold milk (Oatley's what I had) but the buns proved nicely in an hour at about 90F.
My 1st try was following some notes from a relative, which were about 65% hydration all AP flour, and came out much too dense/chewy.
Looks great! I'll have to give this recipe a try. Bao are one of favorite foods but I've never had good luck making them. They never turn out as fluffy as I would like.