Well, the only thing I'll say is, if you set the co-pilot's gain high enough to right the aircraft when you get in trouble, then it's going to fight you when you're trying to make that "nose down approach with left hand turn" landing run. It can also become a crutch that will actually slow your progress.

I also think you'll find that PT 19 to be a fairly gentle flyer. Similar to your trainer except for the tail wheel, and I'm guessing the transition won't be too bad.

But having said all this, you're really the only one who can determine your level of progress, AND your level of comfort with flying and landing. I WOULD suggest that you hold off on that purchase until after you've soloed.
Dennis-