Multi layer magma cream farm

Magma cubes spawn on round platforms on the nether roof over a basalt delta. They head for an iron golem in the middle of each layer and end up on wither roses planted in soul sand, which kill them. Hopper minecarts under the soul sand collect the cream into chests. You AFK high above at y 255 so nothing spawns anywhere else. The video builds three layers and more stack on top. It suits a player who needs magma blocks in bulk, for a gold farm for example. The kill floor takes a lot of wither roses, so you need a wither first. Sweet berry bushes work instead at a lower rate.

• Five builders report hurt or dying golems. Keep the whole farm over a basalt delta so no skeletons spawn and shoot them, and check the middle box against the video, the creator's fix.
• AFK at y 255 however many layers you add, keep the top layer 30 blocks below you, and play on hard with render distance 8. The creator's answers to low rates.
• A lever against a hopper locks it and the cream stops short of the chests. Place the levers on the top and bottom soul sand rows first (3:54). Three builders hit this.
• The y 137 in the video is the platform block, your feet stand at 138. A platform one block higher still works, a builder and the creator say.
• Plain hoppers collect through the soul sand, so the hopper minecarts and rails are optional, though one reply says the carts lag less. Top comment on the video.
• Skip the roof carpets, they were a test, but keep glass on top against ghasts. Any solid block can replace the wall glass, and full block floors spawn more than slabs. All from the creator.