Hi Pete,

I haven't done any strip building (yet) but I think this might help.

There's a book by R. Bruce Hoadley called "Understanding Wood" published by Taunton Press, chapter 6 is about strength, compression, tension etc., and how this is all affected by grain orientation etc.

I'm not sure if I understand your description of grain orientation in strips, but there are strength differences (as well as shrinkage issues) in quarter vs. slab faces, and even a few degrees off from a quarter face can significantly affect the force required for shear failure. (This has nothing to do with "shear" clamps...)
Anyway, it's worth a look (worth owning too).

Happy building, and thanks for a great website!
Michelle