Thanks BillyBob for the good suggestions and encouragement.
Tonight, forecast lows are in the low 40s with rain. I think I'll retry the standard HH setup of UC, OCF pad, with a SB sheet - see if I get a better pad-to-back seal with the lighter SB sheet.
I'm concerned that my old synthetic sleeping bag is too heavy to use as an UQ without pulling the OCF pad away from my back... going to avoid that setup for now - especially with the slightly warmer night.
Also going to add a stocking cap on my head tonight... with the TQ, I could feel a lot of cold on my head and face - suspect I had significant heat loss through head.... might add a wool blanket to supplement the TQ.
I didn't have any condensation issues last night. I'll be interested to see how this setup performs in the rain tonight as well. Is all this trial and error normal to get the optimum setup dialed in?