Depends on the concert, as others have said. That being said, uke strings are a "specialty" and the better strings are carefully selected to perform at short, ukulele scale lengths with different diameter strings for sopranos vs concert (sometimes the same), tenor, etc.. Southoast Ukulele's String Guide will help you understand this. On a practical level, strings run from very "bright to very "mellow" depending on how you want your uke to sound. On my concerts, I have Ko'olau Alohis on my Pono mahogany, Aquilas on my KPK Acacia and Kala Reso, Southcoasts on my Mele 6 string concert, and a few concert scale sopranos soon to have ????
Good luck.