Not long after we moved in, I had the bright idea to insulate the roof above our bedroom. I started with the north (sunny, because we live in the southern hemisphere) side, ripping little 1×1″ strips to support thin tongue-and-groove lambriz pieces, above which I installed fiberglass insulation.
I seems fairly straightforward until you recall this was an owner-built house, meaning that the ceiling beams are not only not evenly spaced, they’re not even necessarily parallel. So I could only cut strips for a foot or two at a time before I’d have to measure again, scramble down the ladder and downstairs to cut more pieces, slightly longer or shorter.
Which is part of the reason I didn’t proceed with the south side as well (which btw still gets plenty of sun in the summer).

The problem lay in finishing each row at the top. They ended with a gap, and insulation showing. After staring at that for far too long, I finally decided I needed a solution. It’s a bit complicated to explain, but required more lambriz, clamping and gluing, a template, drilling and installing screws, among other things.

All while balancing on the penultimate step of an eight-foot folding ladder.
One of those small projects that makes all the difference, if only to me. Oh, and one fun detail. I bought one piece of lambriz – 3.3 meters – and this is what was left over when the project was done 😉

Bless the man or woman who finishes projects they start. Bravo! A great improvement!
Well that clarifies some of your descriptions. I will forward to Gundy.