RE: which plane to use for instructing
I have flown the NexStar as an instructor for several students. With the droops and the air brakes, the plane can be a nice trainer... I think it is too unstable after taking them off. I do not like the "auto-pilot" that comes with it and usually disconnect it.
I like the Alpha 40 and the Sig LT40 nice planes...
One plane that you might not have considered is the Radian Glider... 3 channel version... a sweet gentle flier that can get you going...ESPECIALLY IF YOU ARE BOUND AND DETERMINED TO DO THIS ON YOUR OWN.