I posted this to Reddit and it was recommended I post it here too! The process for PID tuning the snapmaker U1 is weirdly obscure, I made a macro to do all 4 tool heads automatically, a guide for just doing 1 tool head and instructions on how to do it!
Personally I still think snapmaker should have it in their automatic calibration sequence with vibration compensation and toolhead offset but hey ¯\_(ツ)_/¯
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