a close to perfect run, i'm gonna struggle to do better than that. details below the fold, but spoilers i guess?
i managed to get all 20 snakes yielding 30 oil for day 8, meaning i didn't have to spend a single coin on day 9, meaning i was able to buy... i think around 16 big worms on day 10. i spent a few more teeth than necessary to ensure i had the DPS to kill all of them, and i could probably have saved a bit more there