Gourds have a long growing season, so planting as early as possible is important. They rely on a good hard frost to harden them as well. Most people who grow gourds for the first time harvest them too early. You can manipulated their shape by growing them in a confined space, but they do need sunlight, so it cant be a solid box.
Usually the smaller the gourd, the thinner, and more fragile it will be. The weight of lead, either shot, or round balls, creat a problem, since the smaller impact can shatter the gourd when its full of something as heavy as lead.
Hungry Horse