Well, you can't figure incremental torque (hence current)
without some idea whether airflow is and will remain
laminar (drag proportional to speed), or is / will go
turbulent (square law or higher order). The bare minimum
would be an extrapolation of the available load vs line
data, to the max planned fan supply.
Why not buy one, try one, read and record? Then test to
fail at 10% higher than plan max over the weekend, the
week, then start ramping more until the smoke comes out.
You still know nothing about production consistency but
you might get out of school early if it breaks easy.