Inconsistant application Volume

I am trying to "spray" a heavy material, almost the consistancy of toothpaste, (around 27500 centipoids I think).  I am pumping it with a 1/2" diaphram pump, through a DeVilbiss fluid recirculating regulator to a Binks Spray gun.

The paste has in it a suspended solid, that I need to keep suspended, hence the recirculation valve.  i am having extrem difficulty in maintaining the consistancy of the spray, it become lighter and heavier no matter what I try.

Am I using the correct equipment?  Where can I get assistance with spraying this thick liquid, I am located near Toronto.