Top photo, lower right, Aquila Nylgut™ uke strings;
Bottom photo, Worth Browns
Then I went to the Southcoast strings, which include both G and a C as metal-wounds. More volume and a nicer tone, but a little harder to barre, and not quite as mellow as I wanted.
Currently the thing is wearing Worth Browns, which thus far, seem to me to be the best for this particular machete. The low-G is unwound, they are all fluorocarbons, much thinner, and have the best balance of tension and woody tone for which I am looking. The trade-off here is that you don't get the sustain of a wound string with a fluorocarbon.
As you can see from the photo, they are, um ... brown in color, compared to the silver/white Nylguts, and you have to look close to see them in the photo.
I was somewhat put off when I bought the Worth's because they cost about twice what the others did on average. Then I realized that each string is slightly over five feet long, which means you can cut them in half and get two for a tenor uke out of each string, so it's a wash.
These are still going flat every minute or so, and it'll take a week or two for them to completely stretch out and stay in tune, but so far, I'm pleased. If I never tested any more, I think I'd be happy with these; however, I still have Koolau Golds and Living Water in the queue ...