The only warming up that will help that bow is a small fire.
You can't "warm" a bow by half drawing it, or rubbing it, or doing anything to it. Think about how much heat it requires to gently move a bent limb. The only thing half drawing does is warm up your muscles.
I've shot with people who will take a 160lb self yew warbow out of a box, brace it and crank it back to 32" in horizontal snow without a problem. If a bow is going to break at full draw, it's going to do it whether you half draw it first or not.
