Hi George,
Lie-Nielsen uses Locktite I think 270. They and Independent saws before make saws that way about 30 years. I yet have to hear about problems with the slotted back. But I've ssen a lot of saws where the bowed spine opens up.
The circular saw blades, that are used to cut the slot, can't cut as deep as you want. On folded spines I see, the blades are hold only by the lowest 3-5mm. So the slot will have more contact.
Cheers Pedder