Hello ccaian,
I am sad to say that the Servo TinyShield is meant for Servo Motors that have 3-pin connectors rather than a 200:1 gear reduction motor that has a 2-pin connector. So you will not be able to control a gear reduction motor using the Servo TinyShield. For the Servo TinyShield, you would want Servo Motors like these 3 depending on your project needs:
If you want to use the 200:1 Gear Reduction motors, you can still buy the Dual Motor TinyShield online with the connectors attached as inconvenient as that may be, or you could potentially ask your local supplier to get new stock:
https://tinycircuits.com/collections/motors/products/dual-motor-tinyshield?variant=4850373492777So depending on what you want your robot to do, you should look into the capabilities of the servos, and motors separately to decide what you need. And make sure that once you have the correct hardware, you have a battery to plug into the Servo TinyShield or Dual Motor TinyShield since the motors require their own power source even when plugged in with micro USB.
**Small disclaimer: you could potentially plug the gear reduction motors into the Servo TinyShield and the motors would spin if inserted correctly to the two right-most pins, but you would not be able to control them, they would just simply be spin when plugged in.**
Let me know if you have any other questions!
Best,
RĂ©na