How to write correctly MSHook and MSHookIvar

Question

I'm doing a Tweak and i use Flex to edit some Obj-C but one of these i cant edit so, i think if i do a Tweak with MSHook can resolve this, BUT NO idk how to write correctly i'm new on this, i want to disable "shootCooldown" but idk if is posible, so this is my code on Tweak.x

#import <substrate.h>
#import <Foundation/Foundation.h>

@interface ControlsWidget : NSObject {
    NSString *_shootCooldown;
}
@end

NSString *_shootCooldown;

%hook ControlsWiget
{

    shootCooldown = MSHookIvar<BOOL>(self, "_someBOOL");
}

%end