I know the desired method of joining HST is not to chain piece triangles together. However...it always seems that I don't think things through well enough in advance to plan otherwise. My question is, when sewing together the HSTs, how do you keep the end of your seem (at the bottom point) from veering off when it hits the feed dogs? I guide the tip along with a wooden skewer until it's ready to slip under the presser foot, but most often the tip will not follow the trajectory and I end up with the end of my seem being less than 1/4 inch. Of course that produces a less than perfect square when opened and pressed. Any advice?