RE: 2 questions:
Installing the pushrods in the NexStar is pretty easy. The threaded ends with the clevis goes to the elevator and the rudder control horns. The end attaches to the servo arm with a "Z" bend or and EZ connector. If you use a "Z bend" pliers, screw the clevis on until the rod extends completely thru the clevis. This will give you a little extra room to make fine adjustments to the surfaces.
By the way, I have found Z bend pliers very helpful when installing pushrods. I use to be bend "by hand" but found this tool more accurate and faster.
Check out [link=http://www.rcplanetips.net]rcplanetips[/link] for lots of information about the Nexstar.
Happy Landings!