Those will work fine. They will probably never even get warm as long as your run that Blue and White controller. Is that a Czonka solenoid? Cool!
I do have another question though. On your rear set of batteries, how close are the adapters to that vented motor? See what I am getting at? Lots of sparks, battery terminals, just a thought. Mabye turn that rear set around and go with a flat bus bar on the rear set to get them away from the sparks from the motor.