Thanks for the comments about soldering. I would say that my soldering skills suck but that would be a lie, and being honest, would require unnecessary vulgarity.
Old Fox's "Tried and True" Method for affixing ribs.
1. Find the appropriate size sinker nails for a #6 screw. I think it's a #10 sinker. Cut the points off and dress the ends. Thread 3or 4 (your preference) of them in either 6-32 or 6-48 (best). Set aside for later.
2. Fit and solder your thimbles to the rib.
3. Position your rib on the barrel in its desired location and clamp.
4. Measure from the bottom of the rib concavity to the center of the barrel wall. This will be your drilling depth. Either set your drill press to this depth or mark the depth on your drill bit with magic marker.
5. Drill and tap your holes with a plug tap, both your rib and the hole. Slightly countersink the rib.
6. Remove the rib and bottom tap the barrel holes.
7. Screw the nails into the rib just enough to use them to locate the barrel holes.
8. Smear a light coating of JB Weld, dyed black, onto the rib.
9. Relocate the rib back on the barrel and clamp it in place. Then screw the nails in until they bottom and snug them up. Allow to dry for 24 hours.
10. Cut the nails off and peen them into the countersinks. File smooth. Properly done they will be invisible. Excess JB can be peeled off with a wood chisel and sanded. It will also stand temps up to 500 degrees, so you can adjust your thimble soldering if required. Because you have soldered your thimbles on, everyone will assume that you also did a helluva job of soldering the rib on too.