Mark, At your suggestion/request, I've carefully reviewed your pano-album-tin box review of Hahn value added products. The procedure you describe for the Hahn album works exactly the same with the Moab 13x12 (similarly, 12" square visible page with 1" punched border). The dimensions of Moab's pre-punched 9x8 (8" square with 1" punched border) requires the same procedure with appropriately adjusted dimensions. See
https://www.moabpaper.com/chinle for Moab's three offerings. B&H carries all, though some are special order. Of the three finishes--Entrada Natural, Entrada Bright, Lasal Matte--I prefer the Lasal because it's whiter, smoother, deeper black, and better contrast and detail, but that's personal preference. While Lasal has OBAs, remember that these pages rarely see direct sun.
I use these papers primarily to make books with a modified screwpost construction but with custom covers that I also print and coat. See attachments. I make books from 5.5H7.75W to 13H15W, where I cut, hinge, and punch the sheets. But the procedure is conceptually the same as what you described.
By the way, I was intrigued by the 5mm error in your pano example. "You will notice that the photo has about 5mm shorter width than called for. I don’t know how or why Lightroom did this." Since I do a lot of printing on custom pages, including panos, I reproduced your example. Your error was mis-entering the cell size. Up above, you correctly calculate 568.6x184.6mm, but then you enter 565.8x181.9mm. My preferred approach is to enter the desired margins (12.7 instead of 0), maximize cell height and width, and check Zoom to Fill, which takes out any fraction-of-an-inch miscalculation and gives the precise desired aspect ratio.
On another topic (I'll go back to the other threads), I'm anxiously awaiting your review of the Epson P5000, which I'm considering to replace my 3880. Your and others' descriptions of the quirks of loading the P800 with fine art sheets is off-putting. I enjoy your posts--thank you.