I want to change my fender MM jazz to them and I currently use the fender 7250mL. Reason for this rounds chewing up frets l play lots of slides etc. plus lots of practice hours. I play all styles of music but mainly 70's rock. Questions??? 1.What flats are around the same tension? 2.Now do I have to change the intonation because of a different string type? 3.Also do these strings have the black silky material on the top that go around the tunning post?