I change my villagers tasks so often, I don't have the patience to change uniforms all the time . . .

Generally, I find the best way to get elders is, if a villager is a master of a task . . . set them to do something else. Never let anybody do what they do best. I've got a village of 12 people, four of them chilren, and of the eight adults, four are elders, and two are going to be, if something doesn't kill them off. If one of them lives long enough to father some more kiddies, he'll make EE easily. (I shut down all the other parents to give him the practice. )