I finally took the plunge and cut a hole in my table that I've been using as a sewing table for years. Got DH to help me cut it and build a shelf to go under it and hold the machine. I wish I had done it eons ago. For me the difference is not just that the quilt doesn't drag on the corners of the table, but even with my adjustable chair as high as it would go I was reaching UP to the level of the machine and my shoulders would ache by the end of an afternoon doing FMQ. And having my chair that high was putting pressure on my legs and causing my feet and ankles to swell.
I did some research and supposedly the most ergonomic position for sitting and sewing is for your both your feet and knees to make a nearly perfect 90 degree angle. Your SM should be at a height where your elbows also make a 90 degree angle when your hands are lying flat on the bed of the machine. The change has made a world of difference to me.