While I am not sure what the best choice is, I know that the higher your micro stepping is the lower your holding torque is. For precision you will want to go higher, but your trade off is power. With that you may have to increase the current to your stepper motors to increase the power. Cooling your drivers will be important and possibly cooling the motors themselves. I would say if you can use 1/32 with skipping steps stick with that, as that will give you the highest degree of accuracy.
Please correct me if I am wrong… I am far from a pro with this stuff.