I don't think it'll really break the game mode lol, they arent worth much on normal mode and only irons who already have tbow will really care about them. I actually enjoy Puro Puro sometimes but it gets crowded with even just 1 other person there.
There's many things you could put them in: Vote shop, pkp store, daily task shop. Imo all of the shops need a rework anyways.
Could also instance puro puro for higher donors, add more d imps to puro, increase rate on d arrows, increase quantity on d arrow drops from puro, increase the amount dropped at chambers of xeric as currently its not very often or a large amount you get.