Rather than wool i think we should use flagging tape. I have ordered some after having no luck finding any at any DIY shops. The tape is non adhesive and has some stretch in it and seems fairly strong- unlike wool which is likely to snap when stretched too much. As this tape is wider than wool as well it will pick up more of the projections- and created bigger shadows which may look better and intersect the space better. This tape also comes in a variety of colours- but not too many so it will be easy to make a decision about which ones to use. The wider surface area means it will be easier to attach the tape to the walls and wooden panels as well.
The only issue is that we cannot get this tape anywhere other than online so we have to be organised in ordering it and making sure that we have enough before the event.