I have been spraying Benjamin Moore's Impervo. It is a water borne
acrylic. After a lot of testing I can now get a very acceptable
finish. The equipment I have is a 4 stage Fuji with a gravity feed
gun. ( Don't let the gravity feed notation fool you. There is a tube
that comes from the turbine and into the top of the cup to pressurize
it.) A nice feature of the gun is that the cup can rotate relative to
the gun, so when the gun points straight down, the cup can be
positioned straight up.

In any case, I have found that adding 10% water and a bit of
extender makes a world of difference in the finished product. I have
also found that adding too much water sprays well but causes the
"satin finish" to be flat and chalky looking. Too much water can
destroy the final finish!

My $.02

Len