I have only tried the medium tension 1st string, which measured .024/.60mm. It wasn't for guitar but for a ukulele, since they basically use classical strings, just packaged for the uke. Great strings though.
Strings by Mail sells the Savarez .60mm string you are looking for though. They do ship internationally as well. They have an 800 number and Matt is always willing to help however he can. He has opened packages and measured diameters for me before, so I think he would do that for the 3 sets of Knoblochs (which he carries) as well
Here is a link for the Savarez single string. He sells them in both 1 Meter and 2 Meter lengths
https://www.stringsbymail.com/savare...ring-3359.html
Hope this helps.