I started out using powder as well, back a couple decades ago and quickly learned it can fluff up due to static charge------enough so I couldn't rely on it.
Take a small amount of water and syringe, put 3-4 drops of dishwashing liquid in the water to break the surface tension, then weigh the water it takes to fill the hull.
Take a small amount of water and syringe, put 3-4 drops of dishwashing liquid in the water to break the surface tension, then weigh the water it takes to fill the hull.
