RE: set up to correct outside loop roll to right
Aside from the thumbs issue above.
Dont push so hard, your probably making the loop too tight.
Instead of forcing the plane around the loop, make the loop large enough so that the plane will fly the loop.
In alot of planes if you push too hard on down elevator, because the rudder is facing down, it will try to snap. The ultimate biplanes are notorious for this, especially if the CG is far back like we normally have for 3D airplanes.
Other things like dihedral, also play a factor.