I built a 16' crane and needed to see what the heck I was shooting. So I did this. And it works surprisingly well, I just need a small piece of cloth to go over the space between them so I don't get reflections.
Also if anyone is in the Chicago suburbs, check out Powder Coating Specialists in Brookfield (and come say hi to me, I'm in the same town.) They quoted me only $120 to powder coat the whole jib black--quite a deal if you ask me.