Thanks!
More progress today, part of our hood fitment has been hindered by the hinges. When closing the hood they didn't want to close properly and the back corners of the hood had to be pushed down by hand. Don (acardon) on Trifive website suggested replacing the original shouldered rivets with some bolts and sleeves. We hadn't heard anything promising with the reproduction hinges, so what did we have to lose.
First to come up with a hinge spring removal tool...
Now to disassemble the hinge and remove the rivets..
Some 3/8-16 rivnuts were used to make some spacers, and used the lathe to trim them to size, allowing a few thousandths clearance. All of the rivet holes were drilled out for the spacers..
Here are the results, click on the pic for video
Thanks much to Don for the suggestion!