I'm joining in a little late but I own the g303, g402 and g502 and the g402 has noticeable worse tracking on the steelseries qck pad than the logitech g440 hard pad
Just plug both screens into your main card. And to the people saying you can't use different gpus, I have succesfully used 2x760 for main screen and HD5870 for 2nd screen in the past, you just have to have both drivers installed