Aye you want to shorten for more boost but i wouldnt knock the boost all the way down then readjust with a boost controller. You want some pre load on the actautor or you'll end up with a slightly more laggier response. Set the boost manually slighlty below the point where your gonna have the controller take over.
I.E Pre load it to 1 bar then set the low boost on the controller to 1.1.