thats a 951, so the adjustment should be all the way down, stock. its the 787 that the setting is flush. but its really a matter of personal preferance. when the adjusters are all the way down, the raves open later, providing greater lower end torque. when adjusted flush, the valves open sooner reducing lower end torque, but boosting midrange-upper end torque. it really doesn't matter where they are set, as long as both are set to the same place.
personally on my 787 xp, i have mine set all the way down.