Maybe try automating the coal being dropped, so you can go do other things after restocking the fuel supply. Check out the Open Crate page in the Lexicon for some inspiration.
I usually bulk-craft Hydroangeas so I can get a trickle of mana coming in while figuring out how to automate other flowers. Making charcoal from a tree farm could feed your endoflames, with Munchdews eating most of the leaves.
Another solid option is the Gourmaryllis, you can feed it a long streak of items (like rotten flesh, fish, uncooked crops going all the way to cooked meats/stews) for increasing amounts of mana. I like to use a Hovering Hourglass and Animated Torch to feed it four foods that I can easily farm.