I am with Holice. It also depends on what machine you have, too. It sounds like a tension situation....if it s a longarm, the number of stitches per minute can be faster then it is on DSM. The tension is generally loose both on top and bottom for the longarm. Looks like the tension is extra loose on the bottom and the top thread is tight on your machine. It helps to check the tension first. As far as the needle goes, it is a matter of experimenting to see what works best for you, especially if you are using DSM. Topstitch needles is my favorite because the hole is longer/bigger. It puts less strain on the thread. I use size 16/100 needle most of the time for quilting.