G string for a baritone uke ?

I popped a string today. My Koloa Baritone is about 3 months old. Had no spare set of strings (I have ordered 3 sets of D'Adarrio J68's now) so I tried my local music store with a screen print of the J68 package as a reference. The G string needed a 30 (nylon) wound metal. I ended up with the wrong diameter string and it is way too slack.

What brand and diameter string would work for this ?

Thanks

David