Insturment used to measure the diameter of a string. A micrometer works just fine and is more accurate than a typical string guage which has calibrated slots.
For drop G tuning on a 7-string guitar, it is recommended to use a string gauge of .070 for the low G string.
For a 7-string guitar tuned to Drop G, I’d start with a .068–.070 gauge for the lowest G string. A .070 is a good starting point if you want a tighter feel for heavy riffs, while a .068 may feel a little more flexible. The right choice depends on your guitar’s scale length, picking style, and how much string tension you prefer. Longer-scale guitars may work well with a slightly lighter string. If the low string feels too loose or sounds muddy, try a heavier gauge. If it feels too stiff, try going down a size. Just remember that moving to a much thicker string may require checking the nut slot and adjusting the guitar’s setup. I’d choose the gauge based on how the guitar actually feels and sounds rather than following one recommendation blindly. I follow the same practical approach when looking through different products and accessories on sites like Gonish Market: check the details first and choose what suits your needs.
it meant for either a light gauge set with a high E or A string on a heavy gauge set.
What gauge string you use is all about personal preference. There is no gauge that is "good" for it its what you like and can use comfortably.
The standard acoustic string gauge used for most guitars is typically light or medium gauge strings.
For drop C tuning, a common and recommended string gauge is 11-56.
The standard string gauge for acoustic guitars is typically light or medium, with the most common gauge being .012 to .053 inches.
For dropping a 7-string guitar, it is recommended to use a heavier string gauge, such as 10-56 or 11-59, to maintain proper tension and tuning stability.
For tuning to drop C on a guitar, a string gauge of 11-56 is recommended.
The standard acoustic guitar string gauge used for most guitars is typically light or medium gauge strings.
The standard measurement in millimeters for the gauge of a guitar string is typically between 0.008 to 0.059 millimeters.
The recommended string gauge for drop C tuning on a guitar is typically 11-54.