IMHO, size and weight of pup has nothing to do with ears standing, especially at this age. Phoenix's ears popped up at around 12 weeks and stayed there, even through teething, and he was a bit runty. Your pup is still young, let things progress as they should. They may go up and then drop again due to teething, at the very least wait until that stage to see where you are at. On a personal note, my long haired GSD had soft ears, I tried taping and glue, I wouldn't do it again.