I think you have answers regarding the materials that the tin is made from.

I have a 14-month, 8-oz tin of H&H AJs VaPer that appears to be doing fine. Every few months I flip the tin to prevent the bottom contents from ageing more rapidly.

I assume that Larry's Blend is packed like AJs VaPer so there's mostly settling pressure and that's similar to a mason jar of the same capacity (smaller jars would be less pressure unless you stuff it in hard). Storage pressure is important with Latakia. With light pressure, as in AJs and Larry's, you should be able to age it for several years, but not forever and, as a moderately full English, 3-5 years would be a good target for its use.