I have an old toy I got as a kid that I modified to turn hot glue to make a perfect egg. Been working on a design that will turn multiple hooks at one time so a person can make a good dozen of these at one time.
I have also tied some using a pin and bead:
I wanted to move to rubber eggs because of softness of the eggs, that and the cost of quality beads and glue sticks. If my calculations are right, I can make a couple hundred rubber eggs for a couple bucks and have a myriad of colors. Not to mention dual colors, eye spots and whatever I decide to do to the egg.
If it really isn't workable to make a quality rubber egg and have it stay on through many casts then I will stick with the others for fly fishing.