Truly large items from clay present a challenge. They take a lot of materials but they also require a great deal of curing time and it’s hard to be sure that every section has cured enough. You get around this by using armatures in things, stuff like aluminum foil or wire. Either way, large items, such as larger beads can be heavy especially in quantity.
Making large, hollow objects to save on weight, cure time and materials presents another issue. Here’s a method to create large, hollow beads using a wash out core. The tutorial uses sugar but I’ve found cornstarch packing peanuts
work well and gummy dough made from cornstarch and water works fine as well.