In my area I see a number of what I believe to have identified as Norway Spruce. They were obviously planted as landscaping long ago. They are very tall. We have two on our farm that are very tall and straight(about 24 inch dia). They have many branches though and thus many knots. The question is, are these useable as posts in a TF?

Hey BB, Don't know of the Norway Spruce, but they stood as trees so I don't see how they should not stand as posts at least.

As far as knots. I read and heard that as long as the knot does not cover more than 1/3 of the face, then ok

Norwegian Wood........there is a song in there.

"I once had a squirrel..."

Little known, unverified fact (I heard it somewhere):
The original words were "Knowing she would" but that held too much sexual innuendo for the censors, and The Beatles were told to change it.

spruce is good and strong, the timbers can twist, so you should cut a couple of extra timbers if possible. Not a good wood to chisel, but saws ok...

By twist, do you mean right after you cut it? Does that mean you should let it dry before cutting it for the frame or cut it for the frame while green? I was thinking as I had asked in another post, to remove the bark, and sand it smooth, leaving the character of the knots, bumps etc.

Cut it down, mill it out, and cut the joints and assemble as soon as possible to prevent the timber from twisting....

I spose if I could create an ideal situation, I would mill some extra timbers, give them about 4-6 weeks in a well made pile, then cull the worst timbers and cut joins in the rest, and as Jim says, assemble asap.
Spruce does stabilize once it's dry, but no fun to cut at that point, just ask my last TF class, we used 5 yr old resawn spruce for a set of top plates. Nice and straight but very tough chiseling.