I plan to practice quite a bit before I spray the screen. I ended up buying a gallon of the Burmuda Beige initially so I will likely mess with that. I noticed that the spayer can spray in many different patterns. Do you think the horizontal spray making vertical stripes would be best or use the round spray with vertical stripes?Mech has the Wagner CS, so he can give you better details; but as a general rule-of-thumb I would dilute the BW mix with 30 percent distilled water (mech used tap water and got away with it, but I tend to err on the side of caution ). For a normal 40 ounce BW mix that would work out to 40 times 0.30 = 12 ounces of water to thin for spraying.
If you haven't sprayed with the Wagner CS before, always practice on something other than your screen. It takes a bit to get used to seeing and feeling how the paint goes on.
If the roller marks are too appearant, you may have to sand them down a little, but only do this if it really needs to be done - it could be a real hassle on a BOC screen and more harm than good could result.