Barry,
Your vent line is fine. The only thing I do with mine is wrap it around the back of the tank once to keep fuel from flowing out the vent line when I am inverted or on a downline. The vent is only to keep the tank from developing a negative presure and it works even if its upsidedown. You may want to try the pump plate hose like bubbagates suggested. I always do that myself also and see a difference in the planes performance.