Give up on silent fans and get some delta's
, then all your CFM problems will be out the window.... probably literary. They can be fan controlled..... if you have a 30 Watt controller per channel.
Delta TFB1212GHE
Specifications: 120x120x38mm
220.01 CFM @ 4600 RPM,
65.0 dBA, 29.40 watts, 2.45 amps,
Maximum Air Pressure 26.44 mm H2O
Yup, 220CFM at just a mere 65dBA...... Maybe not.