How to select a common mode choke inductance value for power supply EMC filter design?
You may want to read up on this Common Mode Filter Design Guide and also on the TDK site. I advise you decide on the filter you think may be required (if it is) then provide space on the PCB for the component(s) in case it is required. For EMC testing the results may surprise you, as you realise there is no requirement afterall, so you can leave the components out or replace them with 0-Ohm links ... Good luck !