Arching sides on piccolo

I threw together a sanding jig for the arched back that will be on my
line of piccolos. The prototype had, as the original I saw, a
completely flat back. But I've decided an arch would be better. No
dome though, a smaller curve lengthwise will suffice.

But I am being harassed by the customers! They write snide remarks on
forums and nag about these toy ukuleles! I tell you, some people...