Gauge, material and construction are separate variables, and pitch and scale length change how a given gauge feels. That's why we'd never reduce it to a rule that light always sounds thin and heavy always sounds big.
What a heavier gauge can change:
- Feel: firmer, with less flapping in low tunings.
- Output: more string mass over a pickup, or more energy into an acoustic top.
- Attack: often tighter under a hard pick.
What it costs:
- Harder bends and more fretting pressure.
- Possible setup changes: relief, action, nut slots and intonation.
Material often changes tone more noticeably. Stainless steel is brighter than nickel-plated steel, and pure nickel is warmer. On acoustic, 80/20 bronze is brighter than phosphor bronze. A useful approach is to choose the gauge that feels right for your tuning, then pick the material for tone. Our Power Wound Nickel and Phosphor Bronze lines cover a wide gauge range if you want to compare.