The first version didn't have CF on the TE, and I didn't like the results.
The CF prepregs weigh next to nothing and stiffen the wing nicely. I had them lyng around, so couldn't resist trying.
I intend to use my plane outdoors as well. 6 mm will get you one sturdy plane.
I found a smaller CD motor (just under 20gr) and might try this one. Will see if I have the right magnets for such a small bell.....