Third layer glued up OK so I glued an additional 40mm wide ply band around the base of the UTA tonight. This provides some additional thickness for the truss attach points. I will probably stain this like I did with the 8" scope.
I should also have mentioned the former was covered in Gladwrap before placing the first layer of plywood. This is to ensure the plywood tube doesn't become permanently glued to the former, nearly happened to me the first time I did this

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I am using moisture cure polyurathane glue BTW.
A couple of pics showing remasking and clamping for the 40mm strip.