You could. I don't like them because the "patch" wears out quickly. There are also half-height Nylocks (AN364 IIRC) but the jet nuts are much smaller. It would be dicey to keep Loctite from flowing between the keys and sticking them together. That stuff is deliberately very low viscosity and will run everywhere. It would not be my choice. If you want to do that be sure to use the blue stuff. The red or green will need to be heated for disassembly. Personally I wouldn't mess around countersinking a key but if you wanted to do that it would take maybe 0.050" out of the height of the stack. Maybe that's worth it to someone.