DaisyDee I use E-6000. I have used it before years ago to glue silk flowers on a sweat shirt and washing it quite a few times over several years and hanging to dry they held up awesomely. I don't think there will be a problem with them sticking to the ball once out in the weather. It is impossible to get the marbles back off once the glue sets.
I am really having fun doing these and have a few more to do. Thanks for all the compliments.