The decorative strip I made out of Spruce/Cedar diamonds seems very tough - it was hard to plane. It may be due to the characteristics of the Spruce. I wouldn't doubt it if it was stronger than the rest of the hull.

I had to seperate some sloppy joints several times - it was easier to snap a regular 1/4" strip than to break those joints apart. I used cyanoacrylate glue (super glue) to do most of it. I couldn't tell you how it would hold up to a very sharp blow - super glue is brittle.

I'm not a mechanical engineer but the strength of a composite sandwich core is the same principal as a steel "I" beam; to make an I beam stronger you don't beef up the core - you increase the distance between the two skins.