It is what I prefer. If I have to go over six, I try to find a way to keep my lines short. But in general, five to six inches is ideal for a starting point. If you have to make your pressure line really long, then your pressure nipple from the pipe might not be in a place where pressure is consistent.
Everything is different, but all my cars have lines that are within this length range, so it definitely works for me. (even if the rest of the car doesn't