[waialua359]

Originally Posted by Alan Anderson

Doubling up window motors might end up with a worse problem. If one of them runs just a little faster than the other, they'll start fighting each other, and the anti-backdrive feature is likely to lock one of them up. If you don't need the motors to actively hold their position against a force trying to move them, it might be best to open them up and remove the pins.

IN 2011, we used a double window motor setup, but had them coupled together via a shaft to ensure they ran at the same speed when moving our arm.
Given the amount of COTS options compared to several years ago, however, we will never use them again for a similar purpose because it doesnt backdrive after a match.

If OP is set on using a window motor, put a reduction AND use another window motor.