Don Stauffer
One issue is what max pressure can you get from the Smart Jet. Regulators do experience a pressure drop even at low flow rates. Be sure there is enough overhead between max output of the stock compressor to allow for that drop and still get the pressure you airbrush at.
Shouldn't be a problem, Don. The SmartJet pressure switch shuts off the motor at about 50psi.
Based on the specs, the regulator in the link should be fine. The Iwata hose should fit the 1/4" connection.
Don