The other thing about positioning, is to remember that the QD's come apart with just a little push against the button. So if anything bumps that button while the fuel line is under pressure you could have a fire. The first time I did mine, it wasn't until I had everything back together before I realized that one of my QD's needed to be rotated 180 degrees.
Another little trick, and I just learned this, is to buy TWO of the QD's for the crossover line and put a QD on each side. Then, when removing and replacing your tank, you don't have to fuss around trying to fish the crossover line over to the other side.