SalchiPapa Octave4Plus strings have a range of 6 Octaves from C-1 to C5. They make 12 String Guitar String Sets (1A & 1B) that have Octaves on the bottom 5 pairs & a unison pair of High E Strings due to their successful High B String. Now w/ really thin strings, you need to lubricate the Nut so that they slide in smoothly, & you should eliminate as many contact points as we can cause those are the points at which the strings break, as it says so in the included instructions. An 18 String Guitar (6 Groups of 3 Strings):
has the same tuning as a 6 string but has that neat setup (bottom 2 groups: regular octave in the center, octave higher on the left, & 2 octaves higher on the right, top 4 groups: Low Octave in the middle & High Octave on both sides): E3 E2 E4, A3 A2 A4, D4 D3 D4, G4 G3 G4, B2 B3 B2, E4 E3 E4. You'll hear that is has a brighter sound than a 12 String making it sound almost like a gospel Choir. Here's how it is tuned thanks to the high B4 String: E3 E2 E4, A3 A2 A4, D4 D3 D4, G4 G3 G4, B3 B2 B4, E4 E3 E4. If the Highest String Octave 4 Plus makes is a High C5 String & you want the bottom 3 groups as well as the 2'nd group in triple octaves, just drop the tuning down a whole step until the D5 String is available. The Tuning for an 18 String would become D3 D2 D4, G3 G2 G4, C4 C3 C5, F4 F3 F4, A3 A2 A4, D4 D3 D4.