So, have been using Ernie Ball Flatwounds GroupII on my 4 string for years now. Got a 5 string bass but not liking the string tension on them right now. Black silk at both ends and brass ball ends, flatwounds. The B-string is floppy to my taste, sound wise I should probably play them for a couple of weeks to break them in. So what flatwounds have a nice tight B string?