ICEx's stacking thread has some good info. Don't think lvl 9 charms worth it unless you have like lvl11- 12 stones.

Not sure lucky board is that good for high power since charms cost around 140 and adv refines cost 80(somewhat bearable). Sage key seems to be the best . Daily discount shop would be good too if they put 30%+ discounts ..balloon event would be good too if they put charms and cave keys and summon cultivation...recharge can be nice with like 1000 summon cultivation packs for 10k recharge etc.