It's not just thickness that matters, but thickness plus density. Worth (and all fluorocarbon) strings are much more dense than Nylgut, nylon, or gut so the strings are thinner for a given pitch.
Until you get used to them, fluorocarbon strings feel "harder" or "tighter" because the narrowness of the strings is a little harder on fingers. However, the clarity and depth of tone of the fluorocarbon strings is worth (pun not intended) the initial pain.
Someone recommended trying the Worth CT or CM strings so they would be thicker and feel more like Nylguts - just the opposite will happen. Because the strings are thicker they have to be under higher tension to reach the same pitch at a given scale length.
@pondweed - I'm not surprised you are experiencing intonation problems with CTs on a soprano. On all fretted instruments the bridge is positioned correctly for strings at a given tension. When you change the tension drastically (either higher or lower) from what is designed the intonation up the neck will usually suffer (though sometimes you get lucky and hit another "node" where the tension and bridge position work out okay). This is why on most reentrant ukes when you get to the twelfth fret the A and G strings will be a little flatter than the C and E strings. The effect varies with the strings in use, of course, but most reentrant string sets have the A and G under significantly higher tension than the C and E.
I am surprised, though, that it is the C string that is "out" because that string is the same in all Worth sets CL through CT. Are you actually metering the pitch up the fretboard or are you talking about the C being "out" by ear up the fretboard? The latter I could understand because the intonation on the C and E would remain correct while the other strings would probably go quite flat being under such high tension.
Myself, I found I loved the Worth CM but the E string seemed a bit out of whack. I also noticed that the Worth string gages match up perfectly with various sizes of Seaguar fluorocarbon fishing leaders, so I have started using my own sets that are equivalent to a worth CM set but with a slightly lighter gage E string (.0244 vs. Worth's .0260).
So far, I've used the following sets on concert scale ukes (both longneck soprano and concert) with great results. I've also used this on a tenor and it was pretty good though a little light on volume - the strings are lighter than typically found on a tenor. Surprising, though, intonation was still quite good on the tenor.
G - (.0224) Seaguar Premier Fluorocarbon 40lb leader
C - (.0291) Seaguar Fluorocarbon ("blue label") 60lb leader
E - (.0244) Seaguar Fluorocarbon ("blue label") 40lb leader
A - (.0205) Seaguar Fluorocarbon ("blue label") 30lb leader
I've also got a tenor strung with the above but with an unwound low G that is:
G - (.0358) Seaguar Fluorocarbon 90lb leader (note this is sold as their "big game" line and is packaged differently)
That works pretty well for low G tenor, though as noted the strings are a bit "light" for tenor and volume is down a little as a result.
I've also just ordered a spool of Seaguar Fluorocarbon ("blue label") 50lb leader (.0260). This size appears to have been discontinued by Seaguar but I found a store that claims to have some in stock. This size will allow me to make full-tension tenor sets similar to Worth CT. I.e the following:
G - (.0244) Seaguar Fluorocarbon ("blue label") 40lb leader
C - (.0291) Seaguar Fluorocarbon ("blue label") 60lb leader
E - (.0260) Seaguar Fluorocarbon ("blue label") 50lb leader
G - (.0224) Seaguar Premier Fluorocarbon 40lb leader
BTW, I give this information not to encourage anyone to compete with Worth - this stuff is fairly expensive and unless your time is worthless (pun intended) you aren't going to make any money packaging strings in your basement. However, I know that there are other tone junkies like myself who can blissfully spend hours comparing strings, etc. I bought all this leader because I was almost happy with Worth CMs. The up side of being a nut case, though, is that I won't have to buy strings for a long, long time!
John