i definitely would not cut channels in the frame.
either buy of make something like this.
Sick Bike Parts
if you are talking about pulling your sparkplug wire from the cdi, it unscrews counter clockwise. if it is stuck, there might be glue holding it. try digging @ the glue & unscrewing it..
i personally would not use a duel brake pull for both brakes.
more change of both tires locking up. the tires won't track if they are both locked up. then you could go sideways.
think about how a car always always has more front stopping power than the rear. the rears can still roll to "rudder" so the car will more likely go straight.