Changing from high g to low G

Hi everyone.

I'm lucky enough to have 2 ukes, a concert and a tenor, but at the moment they're both strung high g, so they're tuned to exactly the same pitch, and the only difference between them as far as the sound they make is concerned is that the tenor has a slightly fuller tone and a little more sustain than the concert. I play both of them, but tend to use the concert one for songs which involve more strumming and the tenor for fingerpicking and chord melody pieces.

I decided I would like to change one of them to low G tuning, probably the tenor though I've not quite decided yet. I found some videos on YouTube which show how to change strings on a uke, but I don't know if I would be best to change the whole set, or if I could get away with only changing the g string?

Both ukes currently have the bog-standard Aquila nylgut strings on them...I also thought, if I'm going to have to change all the strings, would it be worth upgrading to fluorocarbon strings while I'm at it? Both ukes are Ohanas, so reasonable quality, but still beginners' instruments, though on checking the specs for them I see that the concert has a solid mahogany top (but laminate back and sides), while the tenor is solid mahogany, so might be a better candidate for fluorocarbon strings anyway.

Has anyone got any experience of changing the tuning/strings on your ukulele? What would you advise?