I FMQ on my 500A, and did several quilts before I read this thread.
It did take a while before I got everything set up right, but now I have no issues. I set the foot pressure to 4, tension at 5 and 1/2, use 100/16 needle. The feed plate is raised and the stitch length is set to "fine". I prefer slightly longer stitches in my quilting so I do not "race", just take my time. The hardest thing was to get my tension right. I can rip out stitches pretty good now! I keep this machine set up for quilting only, and do my piecing on the Kenmore Rotary.