Tonewood for cigar box uke?

Hey Guys, as you may know ( or not ), I'm building a cigar box ukulele. Im thinking maybe a spruce top, redwood top, or maybe a cedar. I was just wondering if you have some other suggestions for tonewood for a good bluegrass-style ukulele.

As no one else has chimed in as of yet, here's an amateur luthier opinion.
Ive built several cigar box ukes but always with the wood of the box (usually the bottom) as the soundboard. All of them have sounded good and some of them great, usually the cedar/redwood ones that I have thinned and braced, but I've had success with an unbraced plywood box too.
My best advice is not to worry about it too much, especially if you have something on hand. Just go for it, give yourself permission to make a a few mistakes, and take that experience to the next build.
Chester