I came up with an idea:
Since those foam boards come in packs of about 5 or so(?), I could make multiple props. I'm probably going to be at Abunai the entire weekend, so all three days. If I have the time/material/motivation left to make any more, I could make 3 props! One for each day. One would be Tsumugari, the second would be the Reflector and the third one would be a paintbrush I think.
I could attach the Reflector to my obi using metal wire or something.
Well that was the idea that just popped up in my crazy brain :P