The lift caused by the skirt lifting fan is all about leaks at VERY low pressure. SOO.
You need a large volume of air at low pressure. Sounds like a job for the most efficient air mover in model land.......a 2 bladed, slow speed electric prop. Very much like a helicopter blade in action. 1 central blade may work or you may be forced into a 2 propellor setup. Enough slats & openings in the main deck will be your biggest problem. The holes should be right over the spinning blades.
Can you post a picture or drawing with some dimensions to give us a idea what we are working with ?