A simple answer on glass plates then. With silver halide in gelatin, you only need one coat. Pour the emulsion onto the center of a warm plate and rock the plate until it is evenly coated. Let the excess drain evenly from each corner by tipping all for corners down in turn and then let dry. That should do it.

Do not coat unwashed emulsions on glass plates. They will not adhere. Use an aldehyde hardener for best hardening and adhesion. If you have problems, a gelatin under coat will help.

Make sure plates are dry and free from oil before coating.

A bit of Everclear (ethyl alcohol) and spreading agent will help the coating.