2% lanthanted is the best all rounder. Purple are supposed to be good and I have a pack, not tried yet. Unlikely I will tell the difference between them.
Thorated are often said as best but the downside of being radioactive and a bigger hazard for grinding is not worth it. I cant tell the difference.
Yes you can do zinc plated but you must wear a respirator to avoid the fumes. Zinc fume fever wont do any long term damage but it is extremely unpleasant. It will coat your cup and be annoying but it can be done. The zinc will boil off at welding temps.