Work in the 15–30 PSI band. Around 18–22 PSI suits properly thinned acrylics for general coverage; drop toward 12–15 for fine detail with very thin paint; climb toward 25–30 for primers, metallics, and thicker-bodied colors.
Set pressure with the trigger pressed (working pressure), not from the static reading, and treat PSI and thinning as one dial: if you need ever-higher pressure to move paint, the paint is too thick.
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