RE: Space Walker and PT-19 similar?
Krashkart
One of the main issues that I have found to be practical is visibility. Gray Beard suggested that in his post. Once a student pilot learns to fly the plane and land it successfully, the next step is learning to fly it well. Seeing it clearly really helps in this regard.
I chose the Tiger 60 mainly because it was bigger than my trainer and I could clearly see what it was doing, especially on landing. When it was coming in, and at about a few feet above the ground, "tapping" the elevator to produce a flare maneuver was clearly visible to the point where I could actually see the elevator move.
Once I started seeing this, I began to realize how delicate the "tap" was and how much or how little stick movement was necessary to give a nice and smooth landing. And of course, this translates to better in-air handling because you learn what stick movements will do what and how much or how little is necessary to do something.. like a nice roll maneuver or a smooth turn. The simple stuff.
So, if you decide on any airframe type, from the Tiger, Four Star, Stick, whatever, (and I would listen to what is said above about the tendencies of some of these "warbird" type airplanes, especially when considering a second plane) I would focus on becoming a better pilot and learning how to make the plane do what you want it to do rather than have to deal with what the plane wants to do.
Best of luck.
CGr.