I see your picture and I dove a little deeper into Chappell's book to see some of the joinery he recommends. We did a frame last summer that initially had most of the same joinery. We replaced many of the connecting girt/plate tenons with splines with those concerns for assembly. We also didn't have the tenons on the bottom of the post. Taking care not to snap those tenons on the end of the post will be the thing to watch out for. I haven't used tenons that long on posts so that is the new part to me.
That said this is how I would try it.
After the first bent is up and braced, I would place the bottom girts on a stand with the knee brace into the first bent in. I would probably temporarily gusset the girts to the first posts so it doesn't fall out on someone. Raise the second bent and get it started in the sill mortises. Then as you lower the second bent you can get the first floor knee braces and the girt tenons into the second bents posts. You can put a couple come long or ratchet straps to snug it together on each side. Then drop it down all the way. With the bent completely dropped down you can let a little slack in the straps leaning the second bent out and creating a little gap in the girt. Make sure you don't give the girt enough room to fall out. With luck that should give you enough space to drop in the top girts.
As Tim mentioned chamfering/tapering the top of the tenon on the wall girt will probably be necessary.
