Ah, so you are about to make a SatNOGS rotator but a bit confused about using the encoder?
Unfortunately I can’t directly answer to your questions because AFAIK nobody had built the two versions of these and compared it 1:1 on the performance.
But, like I said above, encoders are needed if you are using DC motor version only. I can’t tell about using DC motors as I’m using stepper version but from what I saw, using stepper is more simpler at the cost of using open loop system while DC is more complex with the need of encoder but with more torque.
The documentation can be seen over here and it’s for version 3.1 even though the first picture and title is version 3. The main difference is the version 3.1 have beefier 3D printed parts and the top/bottom box have same width (unlike the version 3 seen in the first image of the documentation).
If you still has any questions, feel free to ask. I’m not the original maker but I’ll help you as far as I know 