sorry to revive this old post but......corageus i wanted to ask you this question
i made my iron farm 2 of them stacked 66 blocks between them like you said:)
the problem is this that if i go higher in altitute the water will start freezing
how do you deal with this because you can't place blocks on the edge , mobs will start spawning
any ideas ? thank you
Mine isn't built in a cold biome so I don't have any freezing problems.
i have an iron golem farm but its super slow .... i am thinking to building a nother one but i need to make it 100 blocks on top on the each other and the thought of getting the villagers at that hight makes me throw up ...
Mock villages in an iron farm only need to be separated by 66 blocks.
There is room to stack 3 villages above sea level. I made a double stack in my iron + gold farm.
This farm was created back in version 1.8 and is still working great in 1.12.1, although now it's an iron+gunpowder farm.
There is even room for another level if you build it deep underground, so you could stack up to 4 villages in one tower.
To get villagers to the upper pods I used nether portals, which also helped me go back and forth to my base for supplies.
Once I had 2 starter villagers in a pod I broke the portal and sealed them in.
I made my pods carrot farms and had a farmer class villager as one of the 2 starters, so they would self-breed unattended and I didn't have to interact with them. This saved me a lot of trouble since I only had to move 24 villagers instead of 60 (2 villagers per pod instead of 10 per village). Also, villagers will self-breed replacements if one dies, which seems to happen for some unknown reason since I now have nitwits in some pods and the farm was built long before nitwits even existed in Minecraft.
As for gathering XP quickly, I use my guardian farm for XP, or go to The End, stand under a 2 tall roof and stare at endermen to gather them in front of me in large groups. With sweeping edge III on a good sword you can make quick work of large groups and get lots of XP and ender pearls.
For killing the wither I usually put a couple of iron golems in the room to soften it up then finish it off with a Smite V sword. Drop 5 or 6 golems in the room and they will do the dirty work for you. Maybe when you get your iron farm working better you could give that a try.