The salt is what makes the castile soap thicken, so if you are having consistency issues, it can be easily rectified. If the liquid turns out to thick, just add a splash more water. If it's not thick enough, add a teaspoon of salt to a splash of water to disolve it and pour in slowly while you stir until your desired consistency is achieved.
To be honest, the thickness hasn't mattered too much for me as it still works just as well - I just notice if it's too runny it goes through the dishwand more quickly.