I have a friend with 4 spot duallies on his rig and they're very focused. I'd descibe them as pencil beams. You can see 4 very distinct spots of light down the road when he has them on. I think they'd be good if you want to fill in a very specific spot that isn't covered, but if you're using them as driving lights and want a nice spread, that's not what they were designed for.
The Dually D2 Driving Lights with 6 LED's are much better than the 4 LED dually spots. I wish I had bought the driving beam instead of the wide/flood pattern.