Cafe Racer Seat

How's everyone attaching their cheap "Amazon/Ebay" Cafe seats as shown in the picture. Im hoping to find a solution where it can be removed with no tools. Keeping the oem hinge would be cool and securing it with a pin would be great or I thought about having wing nuts for easy removal. Any and all ideas welcome. 

I have access to a laser and press brake so I could get pretty fancy with it if there's any ideas out there. 
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