Dvd,
I really don't have any data to go on. I've had trouble finding info about the capabilities of current filter types that I could base my designs on. All I know is I want a better filter than the simple paper types available. I don't like the look of the high airflow, "high efficiency" filters out there either. I feel I can get higher efficiency with a slightly different design.
I'm currently looking at a filter area of about 93 sq. in. and a flow rate of about 250 CFM, maybe going as high as 500 CFM briefly. This breaks down to be a maximum of a little over 5 CFM per sq. in., or, 155 cu. in. per second per sq. in. This is a similar flow to what a paper filter would see, but my filter area is smaller. My filter appears to handle the flow fine even with its smaller area. Also, mine is a full depth filter about 1.2" thick instead of a surface filter like paper. Mine also has a more dense filter media than the sponge type high flow filters on the market, that's why I think I can get higher efficiency. The filter sees only a little dust at a time so trying to collect and examine what comes through can take as long as a year to get a good sample.
I'll try looking for background info to base my designs on at a university library as you suggest. I didn't think there would be much info on this subject so I came here for advice. What really hinders me is my lack of testing and measuring equipment. It seemss all I can do is take my best guess and try it out and hope it doesn't pass too much dust. Thanks.