Thanks for your info and interest in this project everyone,. Personally, I'm more in favor of two leather loops around the flat edges of the canteen (the ~3.75" side) which are used for attaching a leather strap for hanging on the horse in the usual fashion. Wear and tear on the canteen shouldn't be too much of a problem like it was in the old west because there are not very many deserts and steep rocky hills in south Florida to traverse every day.
The alignment holes in the inner rings should allow alternating the rings at 90 degrees if I want to do that, or keep the grain of all three rings running in the same direction. For more layers of rings the grain can be staggered at 45 degree angles. For just three layers like this project has I was thinking of the 90 degree version to give more character to the grain as seen outside the canteen and to possibly reduce warping or cracking.
I'll try it both ways and see how it looks before gluing begins. All four cut layers have been clamped together with bar clamps at each hole position since cutting them. The last part will be cut this morning.