Mismatched controller Question

Hi All,
I’m building a go kart on a budget. I got a gokart for $100.00, a free 2hp shunt motor, batteries from a auto recycler, and a great price on an NPX4834 controller.
The controller is for a series wound motor, I want to make it work with the shunt motor.

Should I parallel the shunt with the armature and then PWM the combination with the controller?

Or should I control the shunt separately and PWM the just the armature.

Is it customary to put a reverse diode across the motor?

I’ll add a solenoid (with reverse diode), fuse, throttle (pot box), and probably amp and volt meters, key switch, emergency OFF button.

Any hints or ideas you can give me?

PS. the motor is a Baldor 28v at 65 amp, 2600 rpm. I’ll have a 36 volt system. A little high for the motor, just have to baby it till we see how hot it gets.