In deciding what string gauges to use, consider the following factors:
Body Style: A general rule of thumb is to string smaller-bodied acoustics with lighter gauges, larger bodied instruments with heavier gauges. A big dreadnought or jumbo will generally sound better with medium-gauge strings that take fuller advantage of their relatively larger sound chambers. Smaller grand auditorium and parlour guitars will sound better with lighter gauges.
Playing Style: Fingerpicking styles are much easier to play with lighter-gauge strings. If most of your playing involves hard strumming, medium-gauge strings will likely be a better choice, though they may prove a little more challenging to new players’ fingers. If your playing is a mix of strumming and fingerpicking, a light-medium string set may be a good choice. These sets have heavier gauges on the bottom three strings, lighter gauges on the top three.
Desired Tone: As you’ve probably figured out by now, heavier-gauge strings will accentuate your guitar’s bass register producing the deep and strong tones that dreadnoughts are prized for. On the other hand, lighter gauges will provide more emphasis to treble notes and can help bring out subtle picking and strumming techniques.
Instrument Age and Condition: Vintage guitars are often frail, and the greater tension of heavier strings can cause necks to bow and shift and bridges to lift. If you’re not sure how heavy a gauge is safe for your guitar, consult the manufacturer, or in the case of vintage instruments, talk to a trusted guitar tech or luthier.
Lighter gauge strings:
Heavier gauge strings: