I am not much help: my coldest photo session, an owl nest watch, was at - 18 C, and I used a geared (Manfrotto 410) head, because that is what I had on hand at that time. If all you do is set up the shot at the tree cavity and then wait around in the cold for Ma/Pa to deliver dead rodent or for kids to stick beaks out of nest, you don't need to be able to change position rapidly. It just doesn't get that cold here in Missouri. Usual winter low temperature photo shooting session is above - 10 C. My two ball heads, Arca-Swiss Z1sp and Arca-Swiss p0, work fine at - 8 C and above. I wouldn't use the Arca p0 for the Tamron zoom, my weight limit for it is around 2 to 2.5 kg max body and long lens.