What I used for these exposures was a 4x5 plate box camera, the holders are for glass dry plates so the metal plates wil fit with the sprung bottom in the holder keeping them in place nicley. I cheked the fit of an aluminum plate(.020 thick) and it was able to slide under the guides of a cut film holder, check first to see.
A wet plate holder can be used as long as there is a piece of glass on the back of the metal plate to keep it from being pushed out of the focal plane by the tension spring on the door.
The number of plates that can be coated depends on the amount of emulsion you make. I usualy make about 8oz. or less than that if trying a different formula. 8oz will probably make 12 or so 8x10? depending on how much emulsion is used wich is determined by trial and error., not too thin, not too thick. but it will go a fairley long way.
Making the emulsion is not that difficult but it takes about two hours no matter how much you make . I most often have broken the process into two parts. 1-mxing,emulsifying,digesting etc. then refrigerating untill the next night. 2-shreading and washing, remelting,digesting,adding finals.
I am by no means an expert on the subject but this is what I have been doing so far.