Hello !
I've in my cupboard the Ernemann 9x12 my grand father bring during WWI at the Dardanelles.
I've used it with film (9x12 size) FP4 using the original plate holders. The trick is to put into the holder a sheet of mount board painted black to prevent reflection.
My lens is the original one (Hermagis Anastigmat 135 mm F:4.5 ) but the original shutter had been changed because the original Compound like one was dead. Alas, the "new" one has it's slow speeds not working as the mechanism is totally worn out.
Try it, use it, love it !