RE: The best second plane
The Black Horse Speed air, and Graupner Super Air are really the only choices you have listed that would even be close to a "Second Plane".
Here are some excellent suggestions for your next one:
GP Easy Sport
Glodberg Tiger
Sig 4 Star 40
GP Rapture 40 <-- Take a look, it's new, and really nice
Midwest Aerobat ARF
Anything in the "Stik" family