Jim -
So your opinion is that I could order, cut the joinery, and then stack as you propose in your drawings, sealed on the ends and then let it sit a few years in an unheated barn? I just don't want it to "move" so much that I can't put it together when I'm ready. Are the smaller timbers in your drawings rough cut 4 x 4's, or could they be smaller?
Thanks!
Bob