I think I'm going to reinforce the wings as he did:
And AJ Baker notes:
You have a couple of choices to enhance the strength of the wing spar.1. Drill (see 1a) out the spar hole and put in an 8mm CF.1a. To make a "drill", wrap and glue a piece of 80 (or60) grit sandpaper on the end of a 7/16" dowel rod and drill out the spar hole - takes about 30 seconds.1b. Install new 8mm CF spar with the old 6mm spar slid inside it.1c. OR - put 3-3mm CF tubes inside the new 8mm spar.2. Almost as good - Put a 4mm CF tube and a 3mm tube inside the existing 6mm stock tube.