I used NazDar enamel solvent base ink, I think it was 5900 series and thin with their thinners or I used the matching one shot lettering enamel. But paints have changed a lot since I screened printed anything. Let dry overnight and it holds up great for guilding. Just make sure you have "snap" on your screen off the surface or it will smear. Use to put bank hours in black outline helvetica (only outline in rub on type) to make a positve to make a screen. Then fill with white gold next day. Use to mount suction cups on my screen, flood coat it and lift into position and squeegee paint on.
Also works great to pre dertermine where you want your artwork, lay your gold down, screen on artwork, comeback next day and remove gold from window. The enamel holds up well through cleaning even if you have small dot patterns in art.
Many years ago I used Shermin Williams silk screen inks but they stopped those in the late 60s or 70s. That's when I went to NazDar.