Yes, if you want to make these dynamic then the Modbus library would be easier since you can use variables to configure the devices.
This shows the library, but the example is for ModbusTCP. The RTU is very similar though, it just lacks the IP parts. You will need FbMbMasterSerial function block. Also, this video was made with the older software called e!COCKPIT that was based on C3.5, so it will look a little different.
