Well yea the flow is better in Y than a T becasue of the angle. Run the line to the end tree as tight as you can the go back and cut in the Y and then go to that tree. It might help when you firt start to hold the Y above the line and move it along the line until its pointing to the low side of the tree. If your not using tubing tools you will want to pull the line tight and then cut a couple of inches off when you put in the Y you'll learn how much as you go.