Does anyone have information on correct landing attitude of a Schleicher AS-K13?

A club I belong to ownes 2 AS-k13'S. We want to find information on the correct landing attitude of the glider. Our flight manual does not give the correct landing attitude (main wheel, tail wheel, tail and main, skid and main.) I have searched the net and can not find any information that was sourced from Schleicher Aircraft Corp. in regards to the correct attitude.