No, you can't add an additional dimmer to the light. Your best option would be moving the drivers out of the tent. You'll need an extension cable for this.
There are two ways to balance the LED panels. You can use a light meter, or a power meter such as the Kill-A-Watt.
For a power meter, to get maximum intensity:
- remove the protective caps from the adjustment holes in the drivers;
- ensure both LED panels are connected to their drivers;
- connect the power to the light;
- turn down the intensity to the lowest setting on both drivers;
- note the power used P0;
- turn up the intensity to the maximum for one LED panel;
- note the power used P1;
- turn up the intensity to the maximum for the other LED panel;
- note the power used P2;
- P(LED1) = P1 - P0;
- P(LED2) = P2 - P1;
- if P(LED1) does not equal P(LED2), turn down the power for the higher LED to match the lower
You can use a similar process to set the power anywhere you want.
Using a light meter is fairly straight forward. Just let me know if you want me to walk you through it.