There is no issue with the redwood used as a veneer. Also a stabilized block will work well for the riser. Problem is finding a piece that is big enough and stabilized. Stabilizing is what they do to actionwood to make it dymondwood (basically).
Coaster, I looked through the slideshow and couldn't find any pics of the redwood. I have done 2 or 3 bows that way and the wood is georgeous in a bow. I unfortunately forget to take pics of 3/4 s of the bows I build and if the customer doesn't post them somewhere, they never get seen. I know that's not good business, but that's the way it is.
Trust me though, you will like it!
bigjim