Vermiculite insulation is a pebble-like, pour-in product that is light-brown, gray, or gold, often with shiny flakes or small accordion-like pieces.
Use R-19 or R-21 kraft-faced fiberglass insulation for 2x6 walls to ensure it fits snugly without being too loose or too tightly packed.
Spray foam becomes tack-free in 5 to 60 minutes and fully cures in about 8 to 24 hours, depending on the product and conditions.