I agree with Panache and KC. With wool, it's the length of the cloth more than the weight of it. Most of your heat will come from what is enclosing your waist. The less there, the better off you will be. That being said, Even in LA you will have plenty of opportunity between October and May to wear a 16 oz tank, and every wardrobe deserves one of those, made to measure.

I have two SWK Heavies, one Standard, one UK mocker, one Renegade canvas, two 13 oz 8 yarders and two 16 oz tanks. I have worn them all this summer andfind, in order of comfort, that the UK comes in first for summer wear, followed by the 13 oz and the 16 oz, then the SWK heavies (mainly becasue the pleats aren't cut out and so add bulk to the fell area). The SWK standard is last - Acrylic doesn't breath well and pills too easily. I'm done with it.