I have a 4.0 and I use the metal 1/4" foot with the guard. I set the needle one click over to the right which is a 0.3 on the screen. You will see the needle move one click over. About the veering off at the end; most of us have all fingers together and in front of the foot. Try placing your index and middle finger to the side on the foot in a "V" form; this should give you more control of the fabric that has passed under the needle keeping it straight. This is the way I solved the issue for myself.