[EricH]

What type of props are those? They look like 9"x something. Are they balanced? If not, I can tell you how to balance a prop.

Also, I'm not quite sure that that cage is going to be enough. I'd put another layer on on top or underneath so that the area of each open area is divided into four areas--if the props do explode, I'm pretty sure they could get through the pictured version. Reducing the open area will also reduce the risks.