See the attached jpeg for what I did although this is a simple Control Screen the Limited range meters can be added to pretty much any Custom Control Panel.
*Created a custom panel in System Architect
*Drag and Drop the Output Level Meters and Limiter Level selector from the amp GUI over to the custom Control Panel.
*Copy the output level meters and drag them down in size to look like a small rectangular LED.
*In the Parameter panel for the smaller meters change the range of the meter to something like -3 to -4db to create a short range meter monitoring -3db.
*Change the meter bar color to red
*Activate the panel
The smaller meters will look like they are flashing 3db before full output. You will also be able to monitor the output, see what you have selected for limiting and be able to change the limiter setting from the Control Panel.
I only created one limited range meter for each channel, that would meter -3db output, but other limited range meters can be created in the same manor to meter for -6 and -12db before full output.