Will the dualscender work with dual fliplines? Probably, but I don't understand why you would use dual fliplines. The dualscender's design does not lend itself to working each cam individually ... the two fliplines could not easily be manipulated singularly.
I use one of those mini dyneema slings for my microcender. It's designed for just girth hitch onto d ring and onto the cam. Use 2 of them for the dualcender.