i wouldn't touch it mate. actuators are set by factory to a specific pressure, they will always open close at the same boost level. if you want to adjust the boost, you need to bleed the air thats going to the actuator. by doing this you're essentially tricking it to hold the wastegate closed for longer, therefore higher boost level. cheap ebay bleed valve is 30bux and will do the job.
in my opinion the adjustment on the rod is simly to set it up initially so at nil pressure the wastegate is completely closed.
that just my understanding so take it as you may.