Butch, Redwood is quite low in density, and can't handle the strain in dimensions that we normally make bows."Perhaps" a real long 75"+ pyramid style with a light cloth, hide or leather backing. I bet some of the old growth redwoods had the density to make a workable bow, but I haven't seen anything like that since i was a kid, and most of what I see is fat ringed, and more like balsa in elasticity.
You will have much more success with the woods you will be cutting

Rich