I am thinking about stepping up a notch on the gauge of strings. I currently use medium lights (45-100 on a 4 and 45-130 on a five). I have also noticed that it is easier to play faster runs when I lighten up on my touch on my right hand and when the action is lower. I just recently purchased a 5 and the low B is nice and tight, but I think it could be a tad tighter. How does the string gauge affect the action (getting the lowest without buzz)? Does the action need to be higher or lower typically? How much does a heavier gauge affect the fretting hand playability? Bass strings are so expensive and a setup for a new gauge is pretty expensive too. I am looking for opinions before I spend some dough.