Just attended a class at Northern Brewer in Minneapolis on this topic. Told we should only be using 3/16" ID line and should be pouring at 38F. Jeff, who led the class, said that's it's key to be pouring at 38 and not just setting your temp controller to 38. He said to measure temp at the first glass, without dumping anything. My chest freezer is set at 36, but I'm still pouring low 40's. Need to figure that out. I would like to shorten my lines as I'm using too much write now which results in about 1/2 glass of less than carbonated beer in the first pour.
I've had kegs for about 10 years and still felt I learned a fair amount about balancing. Also, renewed my desire for cleaning lines. It's really not that hard, but I'm just lazy and end up just buying new line once a year or so.
If you are having problems with balancing and are attending Homebrew Con, I would suggest reaching out to Jeff. Very knowledgeable as I believe he attended training at Micromatic. Put your fears aside about AB as the store still feels the same as it did a few years ago. I still get great service there.