i am cosidering replacing the strings on my bass from obligatos to ub blacks. the diameter of the ub blacks are from the E 3.1-2.6-2.3-2.0 and the obligatos are 2.8-2.2-1.8-1.5 is that enough of a difference in diameter to worry about widening the nut and the bridge. i know the short answer would be "if its pinching the string widen the groves". i have never changed the strings on a double bass before so im hoping someone with experience can ease my mind and tell me that the difference in diameter should not cause me to need to take a file or anything else to my bass. thank