I paln on getting a Warwick Thumb fretless 5 bolt on, And I want to tune it DADGC and occassionally DADAD. I normally use DR highbeams 100-80-60-40, And I will try and get a hold of a .28 C string for tuning up to D without worrying about tit popping. But my thing is, Will I have to change the nut so that the strings dont move around in the nut grooves? Or can I just use something to fill the nut in, if so, What to use? And Also, Do any of you tune your 5ers this way, DO you use the C much, I'm sure I will since Ive been wishing I had one on my 4 bangers, Positives, Negatives about the High C?