You best bet would be to buy my travelling slot coater from Bud at the Formulary. Not sure, but I think that he doesn't use it. It has a 32" blade, made from 2 pieces of tool steel, so it is adjustable. Just the blades cost over $ 2000, as they had to be precision ground from annealed tool steel. The twist on the blades is low enough that it can hold to about 10% slot width at 10 mils, and that is with a 100:1 length to gap ratio! Not easy to do at all. The coater comes with a large aluminum jig plate with vacuum channels which is flat to 1 mil over the whole surface. Also comes with a nice HEPA filter drier which dries 10 sheets 30x40". I usually coated 8 sheets at a time.
Regards - Jim Browning