Ya shorten the rod and your boost will increase, loosen the rod and it will go down from the gate being easier to open and dump pressure. I dont know if one turn will equate to 1psi like your asking.Every sled and kit can very. Your best bet is to put a boost controller on imo. and you can find your desired boost pressure with out taking your tools out.
2nd what he said, i loosened my waste gate rod then added a boost controller for more accurate boost adjustment, worked great. This was on my apex, will work the same with a Nytro.
If you have easy access to the wastegate actuator you can put your
air compressor to it as well. Be sure to turn the compressor down to 15 psi. Tighten the arm until the flapper starts to open. There you go, your base setting it 15 pounds of boost. Tighten the arm one full turn then see how much air pressure it takes to get it to open. You can set your gate to whatever base psi you want I just used 15 psi as an example. DO NOT USE MORE THAN 15-20PSI FROM YOUR COMPRESSOR.