The clicking artifacts may be from the resolution of the expression pedal you’re using. Or you can try re-calibrating it again in System settings. I’m not getting that from Q-Wah here.
In any case, you can compare that to squeezing a wah out of the Sculpt algorithm. Set most of the parameters to taste, with the Env Filter – Sens to 0.
Map Filter Pre and Filter Post to the expression pedal, with a range of 0 to about 75, as a starting point.
I’ve gotten some good results out of CrushStation, as well. Boost up the Mids to 100, then sweep a selective range of Mid Freq with an expression pedal.