Read back a couple pages. One guy says 4 3/4" worked fine for him. Mine flew okay at around 4 1/4" (It was too windy to even get a good trim set up).
I'm going to have to recheck the CG again after I replace the main gear.
I'm already using larger (and heavier) main wheels.
Too much snow (and too cold) for me this weekend.
(I don't have any skis)