People in forums suggest set of #Thomastik Infeld KR116 Classic S, however, these are not typical #nylon #strings and also are very expensive, especially considering I need to buy two sets to make one full re-string, €60.- total. That's kind of insane. I'm not even sure they'd fit trough the rope because these are thicker. The other option is to order correct strings one-by-one from large manufacturer like #D'addario, however they don't offer #ball-end strings for the exact string thickness.