The bridge script or the Zorro script? Zorro 1.42 is running Z3, Z7 and Z12 each with a separate instance of MT4 limited to the assets those systems trade connected with bridge 1.8 (or 1.9 when I want to roast a CPU core or two).

The CPU usage may be affected by the fact that these are running on Linux through WINE and rendering to a framebuffer so I wouldn't be too concerned about the absolute value. I'm more worried about the relative impact of bridge 1.9 (2x usage).