For what it’s worth I’m running these steppers, I don’t remember how they compare exactly to what Ryan spec’ed back in '18. https://www.amazon.com/gp/product/B00QEYADRQ/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
My build followed @uthayne 's build (SOMD - Lowrider Plasma CNC), I upped the amperage based on his experience. I believe he mentioned back then that the extra amperage should help with faster accelerations that plasma calls for.
I’ve never really personally wrapped my head around stepper specs, curves, etc. @vicious1 is the expert, I say start with his recommendations and maybe tweak your way up if you have to.