Thanks once again for this superlative post that will lead us to many excellent purchases for our gear closets and to the "gear swap" forum to make room for those purchases :-)
I think you covered some of this in your response concerning Under Armor base layers but I'll ask anyway. I use merino wool base layers but, I have some very heavy 320 and 390 weight for winter use. They feel very warm and cozy to me, but I suspect, some of that is due to the other properties (wicking, etc) that you mentioned concerning base layers in general.
My question is, at these stout thicknesses of wool, can you determine their insulation properties, as I have been wearing them as insulation, not as a base layer, although I think they function as both?
Even though these wool garments are heavy, I have preferred them for hiking over my Micropuff or my Montbell Alpine Down as I don't view these as durable enough with their thin shells, or synthetic insulation crushed by the pack, or down absorbing all my sweat. I have limited these "puffy" garments to rest stops and camp or to augment my sleeping bag. But, should these wool garments show that they don't really insulate well, maybe I should reconsider my choices.