The Ofna throttle mod must have been the easiest & cheapest mod that I have done yet.
Come time to do the Ofna tank mod, all I had to do was flip everything 180 deg & adjust the linkage.
The stock spring on mine is not strong enough to move throttle enough to bring the servo to the closed position.
Have you tried to relocate the spring to the roll bar? The stock mount for the return spring is a joke. I moved it long before I did the
ofna mod.
Tudogs