the earlier gammill longarms did not have stitch regulators. A friend who quilts professionally has this one and does a wonderful job.
You can quilt beautifully on your DSM. Take the time to practice moving the fabric towards you and away from you. I found that I moved at different speeds depending on the direction. After working to even out the quilt moving in any direction my stitching is getting more even.
One of the most helpful tips I got at a class was to know where you are going with the stitching. When you need to, just needle down, look at the space and decide how you are going to move around the space. Not knowing where you are going will cause uneven stitches....
Make sure that the quilt is supported and not dragging or catching on anything. Start with smaller samples and projects.
Good luck, have fun