By the time you are getting past 65% NEC maximum branch circuit wire fill you have certainly crossed over into poor economics.
Unless it's no more than a drop to a switch, or some isolated emergency circuit run I just don't ever run 1/2" EMT. The labor cost for 3/4" EMT is virtually the same, and the extra cost of the upsized EMT is a joke.
Moving to 3/4" for all overhead rack work means that you need only one of what used to be two items: one bender, one-size of strapping, uniform bends, one size of couplings and connectors; easier inventory control, etc.
All of this work is typically done up in the air, too.
And then there's the ease of passing your inspections and throwing in an extra wire or two when the pressure is on -- with last minute change orders.
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In all my days, my jobs never ran over budget on minor materials. It's the wastage of labor that sinks a project. Tight branch circuit pulls will bury you every time. I once had the displeasure of pulling nine #12 solid THHN into a twenty-five foot run with two-nineties. It took two man-hours just on the pull. Another time I hurt my back -- I could hang by my weight and not budge nine-into-one-half EMT. (That particular run involved three-ways with A,B switching. All over that job the EMT was undersized because the original foreman failed to understand the explosion of travelers required in three-way A,B switching.)
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Your loads sound like residential...
Which would make me think that Romex is the way to go. Are you in Chicago?
