bill Crommett
John: Have you considered that SPF studs are NOT kiln dried the same way that good lumber is ? To try a mock-up out of garbage wood is ok if your pieces are small, but in something the size you are working with you are fighting several variables: Poorly processed wood and long pieces that will move even after assembly. Just thought I would cheer you up a bit.
For those who have never seen a coopers saw, It resembles a giant hole saw and the staves are cut to width and the edges jointed to the precise diameter of the finished barrel. I have never seen a coopers rig for making the huge whiskey barrels.