Can someone suggest the thinnest non-wound low G for me that is not the Aquila red? I don't want to leave the metal string on there long, but I hate fat G strings.
All of the single unwound fluorocarbon low-G strings that I've personally had hands-on experience with on my own ukes, are no thinner than ~0.0358".
Such as:
Worth Brown & Clear (0.0358)
PhD PVDF(
sold in UU Merch store)(0.0358)
Fremont Blacklines (0.036")
DaKine Line (0.0358)
Anything thinner will Likely NOT have enough tension for a G3 note.
Anything made of NYLON will have to be at least 0.050" to get close to G3 in pitch with enough tension on a 17" scale for a tenor, but this is a
really FAT string for uke, equal to 150lbs test fishing line.
Strings By Mail has D'Addario and LaBella nylon single strings, as well as most of the others listed above, and you can also check Elderly, Uke Republic, Just Strings, etc if not, but likely Amazon has only full string SETS and NOT 'single strings' such as you are looking for, so you might want to save time and not even bother with Amazon here (if you were considering them).
I have found that the Fremont Blacklines
fluorocarbon single unwound low-G to actually have
a bit more tension and to be less floppy than in comparison to the others that I listed above. (to be clear this string I am referring to, is
NOT their gold-colored smoothwound polished low-G called the 'Soloist').