If it were me, I would go buy a piece of wood that was long enough.

A friend of mine that flys electric once gave me an interesting article to read. It seems the electric guys don't deal with the vibration that us glow guys do. For this and other reasons they tend to build lighter and try to build right to the edge of the minimum strength needed. The article he gave me was about something called "stress Risers". Essentially what the article said is that you want the flexibility or the rigidity of the wing to be more or less uniform. If one point is more flexible than the sections on either side, you might have a failure at that point. Likewise, if you have a section that is more rigid than the adjacent sections, one of them is likely to fail.
I would be concerned that the un-uniform strength of the leading or trailing edge might create one of these stress risers. A point of likely failure.