Interesting, flipping to 4micro-step gave some odd results.
200steps per, 3000speed, 5000acc = G00 moves pass, G01 F3000 fail
200steps per, 3000speed, 4500acc = G00 moves pass, G01 F3000 fail
200steps per, 2500speed, 3000acc = G00 moves pass, G01 F3000 pass, THCrate at 25% pass
Not sure really what its telling me, it seems stable at the final settings so i've left it there for now.
Not sure why G00 worked but G01 failed??
I hammered the THC inputs and it returned home every time so no lost steps there at THC rate 30% it did lose a few steps.
The motor seems to whine a bit more at 4micro steps.