I collected well over 300 coins on 13-1H using about 25 flasks.
Would you recommend playing on normal or hard when praying for a seadragon to appear? Is that the only way to get AR coins once you max the level?
would play normal, and try to do stages with as many monsters and waves as possible for the lowest flag count possible
i do 9-4 normal personally, i don’t know if that’s the “best” but it was recommended to me some years back by one of the players helping with barry farmz data so i’ve used it ever since.