From what I've seen (and I'm really pretty convinced after seeing Grizz's bat-turn) the 152 flies VERY similarly to some of my high aspect-ratio RC sailplanes.
With those planes, if you don't know what you're looking for, and how to work with it (or correct for it) "very wonky" is a pretty good description of their flight characteristics...
What Grizz did in his film is what I've done with my RC sailplanes. Sometimes on purpose, often by accident. That high aspect-ratio wing will do some very weird things.
That said, I've learned to correct for it with my flying, and have put some mechanical fixes in place as well. Flying-wise, coordinated rudder is hugely important with that wing. That alone will fix most of the problems associated with it.
Another big one though, is the ailerons. Did the RL 152 have differential built into its ailerons? If it did, that alone would make a huge difference, especially if the AH version does not have differential built in. We'd probably have to ask HTC about that, although I guess it would be easy enough to see from outside your plane on the runway.
Differential and coordinated rudder would tame the plane down significantly, based on what I've seen with my own planes. Without it, my planes can be extremely difficult to fly, especially at slower speeds. With it, they're docile, and easy to control.