Ah, now we are back to the basics......

Bernie, the side slip is a result but it's an unavoidable result. If you bank any airplane and it's not in a coordinated turn then it WILL slip. The nose may drop but there is still a slip to the low wing side. It doesn't matter if there is dihedral or not. If you use rudder to correct the flight path as you are suggesting then the model yaws to bring the flight direction to what we want but the air is still coming at an angle from the side with the low wing thanks to the yaw induced by the rudder. This doesn't matter if it's a poly glider or our dead neutral pattern ship. If you tip the wings then there is a lift vector off to the side of low wing and the model will slip in that direction. The nose will drop too but that's another issue. I have no doubt that the greater projected area on the low side of a dihedral wing would produce some righting force but the increase in the angle of attack thanks to the dihedral geometry would be much more powerful. Look at the lift curves for wing sections. A one degree change in AoA makes a BIG change in the lift coeficient. When you figure if the low wing gains one degree and the high wing looses one degree from the same slip angle that's a big difference.

I think this was the original subject that we've finally gotten back to.