Your understand of the drivers seems to be greater than mine.
We do seem to be agreeing that the steppers can be driven from these drivers just fine, as many as you need. If I get some free time I will double check all my math, and the pololu equations.
You seem to be saying that the PLA mounts will limit you, easy solution. Under power your motors, cut some aluminum mounts, install them and power back up.
How much more power do you think you are going to get from the max you can run your steppers on a pla mount vs. the max that they can handle?
I have actually tried running the crap out of my steppers and don’t actually feel a difference above 0.8v setting in the driver that is why I ship them set to 0.7 so no one needs to have active driver cooling. If I can get my hands on a nice force gauge I will post actual numbers. At 0.8 the steppers might get 2 degrees above ambient. And the ones running on the aluminum mounts don’t seem to raise any because it acts as a really nice heat sink.