Hi @blue,
Note that the M200 motor is actually presently unavailable and on indefinite hold, pending some design revisions and production changes. There is no estimated date of availability, but you can modify a T200 if you wish to achieve the same effect, the motor performances are identical.
The M100/T100 has a Kv rating of ~540 RPM/V, while the M200/T200 has a Kv rating of ~490 RPM/V.
Your questions about holding torque and accuracy suggest that you desire to use them as gimbals of some sort, those factors will depend on the closed-loop motor controller you use to achieve this. However, the motors were not intended to be used this way, so you may run into issues with current draw, depending on the controller you use.
As a rough estimate based purely on simulation (not empirically tested), the M100 can achieve a torque of around 0.28 Nm, and the M200 around 0.5 Nm.
-Adam