Make of RC Tank with 500 rpm geared motor

This is a modification of Oger's "MAKE OF RC TANK ADAPTOR PLATE FOR GEARED MOTORS".
Because i could not get the motor from Oger's link. So I use an other gear motor with 500 rpm (https://www.amazon.de/gp/product/B00JR3WX8S/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1).
I use the Sabertooth 2x12 RC-controller (https://www.dimensionengineering.com/products/sabertooth2x12rc). It works very fine with this motor.
The power consumption in the resting state is 0,2 A and and at full power 2,9 A (chain