I use the lower hole. The top hole will make it hit the tires harder because the instant center moves rearward. Try both and see what works best for you.
=Lower mounting hole for more front end raise and farther foreward IC
=Lower hole for higher HP engines
=Lower hole for less/slower "hit"
=Lower hole for less tire/body seperation
=More preload of 1/2 turn on right side for "level" launch when footbraking
=More preload up to 2 - 2.5 full turns for hard preload for instant chassis reaction when on pro tree or want to leave late near end of last yellow
=Less preload to soften or retard reaction times
=More preload when flashing from idle
=Less preload when brake stalling hard on line
=More preload in bottom hole for easier wheelstands