I say give it a shot and see how you like it. I have a few sticks of redwood brace stock from Allied's weekly special page, and while it does split more easily than spruce, I'm not convinced that it's worthless. It's so light weight and stiff, and the color is nice for back braces with darker woods. I might not do a lot of hard percussive playing on a top braced with it, but then I'd be wary about that on a thin redwood plate as well. Don't forget to make your braces a bit taller than usual though! Also, triangular cross section seems a bit iffy, with the point of the triangle being so easily split off. I plan to round them over a bit more than I do on spruce. Maybe not quite parabolic, but headed that way.
But it might be smarter to listen to Mark, since I'm only on #3, and haven't tried gluing redwood to learn what difficulties everyone talks about yet
4 piece tops are definitely good though. Sapwood stripe up the center would look pretty cool, I think
