You are right to say the majority of the travel should go to the throttle. It takes far more servo movement to fully open the throttle than it does to fully operate the brake. You can adjust the pressure on the brake lever by moving the small collar on the brake connection so that it will engage earlier and more firmly when the servo moves. It is often a case of making small adjustments and testing after each time, time consuming and boring but better than a full throttle impact into the kerb. Hope this helps.