even after I did a gain change on the vocal track up to about a +3 or so with the peak limit on, it was still low so I copied it to a second track in order to boost the volume so she can hear it for now.
If this was done in the Gain Change effect (like you said) you simply boosted it by +3 and the Peak Limit probably did very little.
I'd suggest actually running the PeakLimit on the vocal track in real time (instead of the Edit hard write FX like the Gain Change).
Get PGPeakLimit set to where you like it using realtime FX .. then if you really want to go ahead and hard write it do so using the Edit PGPeakLimit effect. Simply use the Save Preset option while using the real time version, then open that same preset in the Edit hard write area ..
They are separate; using realtime FX allows getting the settings just how you want, then if you want to save resources and hard write it to another track you can do so by using the Edit-PGFX path ... I often prefer actually using the PGPeakLimit plugin vs the Gain Change (with Peak Limit enabled). YMMV
FWIW, I find using the PGMusic plugins as being very efficient. Running 20+ instances of these does not cause issues here, so the need to hard write it is pretty rare.