If this is old news, I apologize, but I have never seen anyone suggest this for the Prime Master weapon mode for the pretender shells.
https://imgur.com/kFDj49D
https://imgur.com/WVZWTuF
If you don't fold the Prime Master over for the weapon mode like the instructions and leave them in a sitting position, it works like modes for the Titan Master vehicles for city/base defense.
*For whatever reason, I am not having any luck getting the uploads on Imgur to show using the IMG tags.