Orientation of character controller relative to ground normal?

I'm quite new to 3D programming and have some issues with my player movement.

The idea is, that the character controller always has to stick to the ground (gravity towards the ground normal, but only for this object!)...I searched a lot and found this tutorial:

http://www.41post.com/4123/programming/unity-normal-walker

This helped a lot, but the character movement still is very juddery and there are some strange rotations when the character controllers angle is transformed...once you are at one of the spheres poles, it's nearly impossible to leave them, walking straight around the sphere, too.

Is there a way to refine this or another, better way to make my character controler stick horizontal to the ground?

Thanks in advance. (Sorry for mistakes in the language, I'm german^^)

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