The simplest evaluation would be to find a similar 'factory' or experiences within the same branch (as you are searching here). For this you could ask suppliers of air compressors and complete air systems of advice. Else would air tank size ('reservoir size'), max and min allowable pressure, and max (all valves operating together?) and min (none?) consumption over a given periode give you an indication.
Provided you have no separate backup reservoirs for emergency valves/operation, you will have to have a normal reservoir and filling capacity large enough to give the max operating consumption over the given (necessary) time. Size adaption of tank could go up, and size of compressor down if max consumption periode is short, and so forth.
(PS. Up till now, I have not seen a single pneumatic layout with too many drainpoints and filters, while the opposite is quite common.....)