For custom tunings other than the standard 6-sub diatonic tuning or Stephen Bennett/Andy McKee tuning, you will need custom string gauges. Please use this string gauge caluclator to calculate the appropriate gauge of string for the notes you are tuning to.  The S-12 harp guitar sub string lengths are  33.125″, 32.25″, 31.25″, 30″, 29″, 27.75″.  Approximate recommended tension per string is 20lbs, and no more than 25lbs.

 

For Tonedevil  model harp guitars use light or extra light gauge DR phosphor bronze  and Labella nylon core light gauge harp string sets available at the Harp Guitar Music store:

 

Phosphor Bronze Wound DR Steel Core Strings:

DRHarpGuitarStringsStandard 6-Bass Dyer tuning
Light Gauge

.072 .064 .060 .054 .052 .050
F G A B C D

 

 

 

 

For Tonedevil S-12N nylon sub string light gauge sets use La Bella Nylon Core Harp Guitar Strings:

La Bella Harp Guitar Nylon Core Strings

.070 .062 .058 .051 .048 .045
F G A B C D