Using steady state value in "model" part

Is there anyone who has idea about how to insert exact values of certain variables at steady state into ‘model’ part? For example, in Taylor rule, we need to scale output by its s.s value (y/yss) in ‘model’ part but until we specify initval value and command “steady” to compute s.s , Dynare file does not have steady state value of y. My model is very sensitive to the ratio of y/ys so if I dont have exact value of ys, the results will change quite a bit.

Thank you very much in advance.