Greetings NH and Roger,
Roger, I have been doing a lot of stomping around in Civil War era barns in Southern Wisconsin. The last three were 40' x 100' or larger. They all exhibit the same beam characteristics that you described. All the long beams were primarly pine and hand hewn. The wall plates were scarfed at 22' with the brace under the scarf. I couldn't get on top to see how the rafters were joined. It looked like bird mouth. The posts were oak. As you had mentioned, there were recycled timbers. One barn had several beams that appeared to be pit sawn because of the changing direction of the tooth marks. It is pretty cool to look at these structures and read them like a story.

NH,
Your description of my ideal space is quite close. Unfortunately, I am sandwhiched between two buildings that are 32' apart. I have to comply to local building codes and a 4 hour burn wall on each side. No windows on the sides. I admire the attention to detail that you have been able to put in to your projects. I constantly struggle to maintain the balance between accuracy and an extremely small budget. I am somewhat obsessed with the planning. This is a gigantic first project. Slightly larger than my 1550 printing press. I have confidence in my abilities it is the magnitude that is intimadating. At least I have a small army of volunteers to help. I just have to remember to tell them to take off the armor before we raise the frame.
KM