Enjoy Japan! I find it easiest to build a gossip mechanic iron farm early on - 5 villagers, no zombie - no issues with line of sight on the zombie and zombie wrangling. Yeah it only operates during daylight but it's a simple thing to build more than one and have the golems flowing down to the same kill chamber. 2 villagers in a chamber and breed them up to 5 and have the drop to the kill chamber more than 16 blocks.