All I ever use is the Harbor Freight HVLP gun or the "Three for $99" set like Drew has.
I've used that same Safety Yellow for my Tokheim and I've used Deere/Ford Yellow on a Deco Ped. IMO the yellow yellows are more correct for older signals. It seems the signals got more orangey when companies started painting to Federal Spec colors...the common yellow-orange, green, and black signals are typically sold in today. There's a distinct color difference between Breadpan/Decos and Winkomatics, etc.