tip size to use when power spray painting with rustoleum stops rust enamel?

[disney]

I have a 10" I beam deck over that I would like to paint. I have a Krause & Becker (harbor freight) 5/8 hp 3000psi airless paint sprayer, that I would like to use as it did a good job on the house. I plan to use rustoleum conventional spray cans for spot priming any rusty/bare areas prior to painting. I do not expect to do the I beam in one pass, and honestly I think I would be best with three passed (1 for the bottom side of the top horizontal web and some of the vertical web, 2nd pass majority of vertical web, and 3rd pass remainder of vertical web and top side of bottom horizontal web. so maybe a 6" fan (open to expert/professional advice) but I would still need to know orifice size. local big box stores can only tell me what's on the label, and that is not very helpful.... Thank you in advance to all who have advice (on topic) to share.

 

[Billrog]

It's my understanding that the orifice size would be determined by the viscosity of the paint being used. So you will first have to check your paints viscosity and any paint store should be able to give you a stick with holes in it for that purpose.

 

[Rock Crawler]

Any you add acetone and hardener to it, that changes the viscosity as well.