Like I mentioned before, you need to run the formula to figure out what to set your friction setting at- this needs to be done BEFORE you begin building, because adjusting the friction values will affect your layout!!
I don't remember the formula off the top of my head (I want to say it is : (V out - V in)/Track length, the V-in is your input speed (post lift hill or launch), the V-out is your predicted exit speed and track length is your predicted track length).