fredvegas,
There are many more guys on this forum that can answer those questions better than I can but I will tell you what I think at this point.
I made the mistake of opening too many tins at one time because I wanted to experiance as many new tobaccos as financially possible. That, in my opinion, is the wrong way to go about smoking and learing about the various tobaccos for, at least, two reasons.
1. Unless you invest in air tight jars, the tobaccos in the tins will begin to dry out. For some tobaccos this may be an improvement but for others not so much.
2. I've heard from more than one person (John at the Briary included), when trying to learn about a tobacco, unless your a seasoned smoker, you should smoke the whole tin and not jump around like a kid in a candy store. You'll have to decide for yourself.
BTW, five of those tins were finished up in the same week (Westminter, Maltese Falcon, Navy Flake, Dorchester, and Plumcake). No I didn't smoke all of them in a week, they just ended at the same time.
I have only four opened tins at this point (Davidoff's English Mixture, Scottish Mixture, Escudo, and Irish Flake) and I'm going to finish them before opening anything else.