In the GPO4 graphic user interface, (GUI) there are four tabs on the right-hand side, the second one down is controls. Each knob has the midi control change, (CC) number next to it. Those are not going to show up as controllable features in Logic, but if you insert, (draw or play) those CC values into your appropriate midi track,... GPO's loaded instrument will respond.
If you want to automate pitch, that is not a midi CC. As you may or may not know, some midi controllable features do not have CC numbers, pitchbend and aftertouch/monotouch are a few.
The tuning in GPO's loaded instrument is just below the loaded instrument name. As far as I know, that is not controllable, and you wouldn't want it to be. You want to set that to the correct tuning for the project, then use pitchbend in your midi track to automate the pitch wavering.
Another nice feature in GPO is VAR 1, turning up this knob and leaving it at one spot will randomly alter each note. Just be careful to not use so much that it sounds like the local junior high school orchestra.