The D'Addario Pro Arte Classical Guitar wound D is my low-G string of choice on my concert uke - after lots of trial and error, I've decided I really don't care for the sound or feel of uke-specific low G strings, especially the fluorocarbons.
The only concern I would have is if the tension is too high on a guitar string to use it on a soprano - I can't actually speak to that as I don't know, but I've heard that this is why there are different gauges of strings. Personally I prefer higher tension in general, so I tend to use higher-tension concert strings on sopranos, tenor strings on concerts, and haven't had any problems as a result of the higher tension.