Testing fans is obviously very time consuming. What about tapping into the local science student community? There may be some bright young physicists at the honor high school level or the BSc level that might be interested in doing a project for a science fair or school assignment.
eg they could look at how dBA changes with RPM and disatance to verify the standard ideas on dBA change with distance and the logarithmic addition of noise sources.
Or a fan roundup.
Or they could look at effects of struts on dBA (qty and distance)(requires a little bit of mechanical skill as well to mod some fans).
Have to be old enough to stay up late though!