I would say double natures are the best, im pretty sure there around 400-500k an hour but im not 100% on that since ess has apparently risen in price loads.
Have to agree with everyone else and say double nats. As for XP and GP/Ph it would depend on other things too such as Agility level (not that energy drains as fast as it does on 07) if you're using mousekeys to speed up banking. If you're looking for decent ways to make money though I'd have to say bossing has always been good. The new boss that was released drops some fair priced items, just have to find a team ofc