Snow golem creeper farm

Creeper farm that uses snow golems instead of cats, with no redstone anywhere in it. Creepers spawn on a flat platform over the ocean, sixteen snow golems standing on a bed in the middle pelt them with snowballs, and the knockback pushes them off the edge into a pit where soul campfires kill them. Slabs across the whole floor are what keeps spiders out, and that matters more than it looks, because a spider will aggro the golems and eventually kill them. Twelve hoppers under the pit feed twelve chests. It stacks, and every extra layer needs its own set of golems. Java only. On Bedrock the snow golem AI aims too well and stunlocks the creepers where they spawn, so they never travel to the pit at all.

You only need one carved pumpkin if you shear the head off each snow golem and reuse it.
Place the solid roof first and the trapdoors after, and torch the platform while you build or things spawn behind you.
Any 3x3 gap left in the floor spawns spiders, and spiders aggro the snow golems and kill them. Check every slab. Carpet on every other block works too and leaves only 1x1 spaces.
Sixteen golems is a rough number, not a rule. Too many and the creepers never reach the pit, too few and they never aggro. That is from MushoDen, who designed it.
If the rates are far below the claim, check that the golems are actually shooting. They can bunch up into a single block on the bed, and punching one frees them.
Every layer you stack needs its own set of snow golems. A builder with four layers reports 6000 gunpowder/h.