I usually dont use the tcd's in my car I think they work best when traction is high and the track is smooth.
This winter I raced at an indoor clay track where we ran slicks with traction compound and the tcd in the front was awesome but took the same diff setup outdoors tcd(red) 7k 3k and didnt like it much at all switched back to 5k 7k 1k which I like much better on rough loose tracks.