After corresponding with Ken (k2k) and Brigitte at modellbaumuder I re-hinged the elevator to give 45 deg total travel.
I then had a couple successful short flights, really just hops down a big grassy hill (Awesome video thanks to Gérard):
The first couple tosses (not shown) confirmed Ken's observation that some down trim is required to maintain speed. Despite the size of the wing, this thing wants to fly fast. Once it gets nose up speed bleeds fast and lateral stability drops.
Even with an expert downhill toss (from Bob who knows all), the plane really wants to initially balloon up on release. It takes full elevator travel for a little while to get the nose back down, at which point there is very little flying speed. Then, if you don't hit the ground, it flies quite nice and stably. Most important, it looks really great in the air.
As you can see from the second video, once it hit ground effect it kept going and going...I tried to put it down before I ran out of grass and it just kept flying, resulting in some PIO.
Regrettably the last hard landing (preceeded by 4 more) finally knocked the servo tray loose so I made no further progress.
I am flying with a CG of 25% as recommended. I may move that a little forward to reduce the PIO. Alternatively, I may not need all that down elevator travel for normal flight. At 22.5 degree down, the elevator probably has less to do with true flying and more just acts like a speed brake dropping the nose. So maybe I will put full down travel on a flap switch when needed and fly normally with less elevator travel.
Can't wait for the next test. Regrettably it will be a few weeks...
I gotta say this is one tough bird and looks great in the air!