Just a suggestion from my own experience, don't pack an entire pound into a jar.
Once you open that jar, you need to smoke it up quickly, or rejar it into smaller jars. Opening the jar 3 times a week will dry your tobacco, and no "aging" will take place.
I personally use 4 ounce Ball jars with the 2 piece lids. I get 15-20 bowls from a jar when packed just springy, like you pack your pipe. You can use slightly larger jars if you prefer....6oz or 8oz.....I personally would not go bigger. An 8 ounce jar holds 30-40 pipe loads on average.
This way, you can have some open while the rest keeps aging. And if you have several blends, you can have several smaller jars open, while the rest stays mellowing and aging. I usually have 6-8 jars open, these take me through weeks of diverse smoking.
Unfortunately I have several pounds of "out of production" McClelland blends and others in big jars holding 8 ounces of tobacco. They are between 6-18 years old.
I know many pipers who regretted opening an entire pound that has been aging for a decade.
Again, once opened, you need to smoke it quickly or it will dry out if you repeatedly open the jar.
Just something I learned over the last few decades.
As far as how tightly to pack the jar.....just lightly firm, not too lightly, not hard packed. Tobacco needs oxygen to age properly. The oxygen left in a lightly firm packed jar has enough oxygen to happily age for many years, no need to burp the jars.
In my opinion.
