Hello TMA:
Well quite a project but I am alittle confused, your building is 24 feet wide by 60 feet long, and it is 5 bays with uprights at 8 feet, that doesn't work out, my math says 5 bays at 8 feet apart equals 40 feet in length, but maybe I am missing something.
For starters I suggest tenons on the top and bottom of the posts to be 2" by 7", this allows alittle for shouldering, and I would let the tenons to go right through the upper and lower plates, making them 4" in length.
I would use 1" hardwood pins but others might argue differently, and don't forget to design in wind\sway braces in the appropriate spots.
As for the corners, I believe that the building inspector from your area might have something to say about connections such as this. You no doubt will have to get an OK before you start construction. He may require metal connectors of some kind to ensure the building code is followed.
Good luck NH