Smelt before you light up. The metal fragments are the only part you cannot make by hand, so on a fresh wipe the lantern waits for the first ore to go through a furnace. The fuel is the easy side: a few crafts of low grade fuel from fat and cloth, and the blueprint is known from the start.
One lantern leaves a single fuel over from the last craft. Four use the batches exactly, which suits a base anyway: one for the loot room, one by the door, one upstairs, one spare. Queue them together, then keep a stack of fuel beside them for refills.
Want light on a wall instead of the floor? The tuna can lamp takes less fuel and no frags, but it needs a little research and an empty can you have to find first. Once the base has power, craft neither.
