RE: 4 Stroke high speed needle setting.
9K rpm was peak rpm on the ground, so that would be roughly 8600 rpm richened down. To me, 8600 rpm means too much load on the engine.
Sorry, I don't have a tach reading for the Graupner 14x7 3-blade. Based on experience with Graupner 2-blade props, I am 99% certain that the Graupner 14x7 3-blade would load the engine more than the MA 14x7 3-blade. You might want to order just one to test it out.