Watson, I've had shoulder surgery on one for bone spurs cutting into the rotator cuff and FMQ on the domestic machine was agony for shoulders, back and neck. I got a long arm and find that I don't have that problem even though my machine is not light (it's a Gammill). If I do a lot of ruler work, which means moving the machine one armed, my arm does get tired. I think you were thinking about a sit down machine weren't you? Know it's more expensive but you might want to check into a long arm (used?) as the process is much different. I then found that cutting out a whole quilt was killing my non-surgical shoulder and it felt like rotator cuff again--got the Accuquilt GO Big (electric) and I'm saved! Cheaper than my medical co-pay for another surgery!