Hi John - I just went straight through the bulkhead. I reckoned that there was about 1/2" of Iroko then 1/4" of glass and then another 1/2" of Iroko on the inside which seemed reasonably well supported to me. I used a 3 x3" ply pad under a very large washer on the inside.

It is amazing that Caldo apparently don't know who sells their products. He couldn't wait to get me off the phone. I should probably not reward them by trying to find a distributor but as Taylors themselves recommend the stuff, I would quite like to give it a go.