OUGD406 - Licence to Print Money, How to Mount

I have had some dilemmas with how to mount my work. The brief specifies 2 banknotes to be mounted landscape and fit within 21cm X 26cm my notes fit these dimensions but I would like them to be displayed as one set lining them all up behind one another to get the full effect of the piece. I can either choose one or two of my favourite designs, mount them in a frame and hang them or design a 3D mounting system. The idea I have in mind would be to take two pieces of plywood and connect them together so that there is no movement, I would add cut outs into the wood 2.5cm away from each to slot my notes into this would mean that the notes would still fit within 21cm going backwards as well as across.