Constant current source with shunt fet
I can't comment on your post (I don't have enough reputation) but I can't answer you question either because I don't really understand what u are trying to achieve. 

If your whole purpose is to create an LED strobe I would not build it that way at all.
You got 32 Amps and your 3V3 controlling circuit seems to be directly connected to your working circuit. You should always make sure ur controlling circuit is galvanically isolated from any heavy electronic load.

Instead of MOSFETS you should use optocouplers I would even use 1 optocoupler for every String of LEDs they cost like 3 Bucks and are even cheaper if you buy them in bulk.

After you got that part you can pulse the input of the optocouper with about 3 - 20mA (depending on the optocoupler) using an uC or if you want to build a pulse generator from scratch you can just connect the output of the pulsegenerator to the input of the Optocoupler. If you want to dimm LEDs I would just use PWM tbh.

EDIT
Okay I get it you want to dimm it analogish you can always smoothen the pwm Signal using a capacitor. That way you could limit the Voltage and if you use a poti as Protective resistor you can adjust your max current aswell just keep in mind you need a 2nd Resistor serial to the Poti so you won't be able to go near 0 Ohm. 



This is just a concept and I didn't calculate the values at all.


If you are really into OPAMPS and analog stuff you can go with that schematic of yours. But tbh I was so happy when I graduated that I never have to touch a freakin OPAMP any more. You can always use digital components.