I'm still new to all this airbrush stuff too, but I have picked a few things up.
1st. It's always a good idea when you are new, to stay with what the manufacturer recommends.
After you get some experience and have a better idea of what works and what won't, then you can experiment.
2nd. I think you missed a digit in your question
From what I see most often, 4011 is the recommended reducer. Same manufacturer as Wicked.
Others with vastly more experience than I will chime in shortly.
On a absorbent surface.Like paper/canvas. Is Distilled water fine.
But on a non-absorbent surface or if you are going to use tape, masking film, it is better to use the 4011.
Possibly in combination with the uvls gloss.