You should check this post out!
My record is 290, average is around 60, just enough for extra 20 seals and 1 vault!
I’ve tried to maximize green chests for maximum gems reward, but somehow it’s not quite work for me, as I was spending more time try NOT to make red chests. So now I’m just usually doing my best, might get less gems, but getting extra gem keys are sweet too for chasing Mythic!