I had the Modeltech Great Lakes and flew it for 10 years. It's an ARC kit and I never had any problems. I just sold it last yeat at a local swap meet.
I flew it with a OS 61 Surpass and an 11x7 prop.
I did have roughly 10oz in the nose and 2 degrees of right thrust. I'm not one that's afraid to add weight. I had a GP Corsair ARF that took 1lb of lead in the nose with a 70 Surpass. I was scared but it flew great.

And, as mentioned earlier, there is negitive incidence in the top wing.

Just my .02

Bob