Sorry to inform you ,but cutting 20 gauge with accuracy with plasma is not going to happen.First of all there is nothing accurate about plasma cutting.If you want accuracy you need a laser or a waterjet.20 Gauge is going to warp real bad unless it is simple shapes.You will need to have a water bed also with the water touching the material to help stop some warpage.CNC plasma is nice to have,but by no means is it some miracle cutting process.