I'm leaning toward flood system. Shop will be in garage. Landlord requires that car be parkable at any time because of deal they (well, the developer) made with local zoning. This means shop is workbenches and tool chests arrayed at end away from car-door and on one side. No ventilation except by gravity with big door open. Rack storage system on other wall with usual family treasures in bankers' boxes.
So the concern is eventual film of coolant residue on everything. And I suspect it would happen quicker with a misting system.
Obviously, I could buy some ducting and build an extractor (5 1/4 inch muffin fan) to convey the vagrant mist from the mill to the outdoors - cheap and likely effective and maybe I should just do it. Residue film everywhere seems equally likely if I just brush on cutting oil like I did 55 years ago in the wonderful shop where I worked and should have learned all of this stuff.
O/T but ... The place was set up in 1914 north of Chicago, mostly ran on a single motor with overhead shafting, leather belts, etc. Newest machine (only one with coolant system) was horizontal band saw. Second newest were War Production Board South Bend, some Hardinges,. and a Delta Drill. Everything else had been there in 1918.
Unfortunately (well fortunately for me) I'm the only one who worked there in 1960 who is still alive so I can't find out what we used for cutting oil. The smell is imprinted on me somewhere, but I haven't run into it in years - probably suppressed by EPA. But its use did lead to film on windows - whose cleaning annually was one of my jobs. Might also have been Pipe tobacco fumes -- Oscar Trumbull Scalbom. So it sounds like an exhaust duct will be part of the scheme. I really don't want to have to clean the walls.
BTW, if you think anything I write is nuts, I won't take offense. I spent most of my career doing things I didn't understand and am used to criticism. In fact if I don't get any, it really bothers me.