Use R-13 or R-15 kraft-faced fiberglass or mineral wool insulation for 2x4 walls to ensure proper insulation.
Drying time for wet insulation depends on type, ventilation, temperature, and humidity. If it doesn't dry within 2-3 days, it should be removed to prevent mold and wood decay.
The thickness of R49 insulation is typically around 14 inches. This measurement ensures that the insulation provides high thermal resistance, commonly used in attics and other areas requiring significant insulation to enhance energy efficiency and comfort.