I describe the Aquila Low G string I put on my new Tenor Ukulele in the following video.
You can also get a Red Series C string. Some people believe the results are better when the two low strings are similar which is why some sets of Low G tuning ukulele strings have both the G and C strings wound. Now, instead, you can have both the low strings Red.
Aquila makes Red Series strings to match most of their Nylgut sets when you have low strings. This includes standard Baritone tuning (DGBE) and Baritone C tuning with Low G.
You can read more about Aquila Nylgut and Red Series on the Aquilcorde website.
Here’s a video from Aquilacorde, demoing their new red series string.