I bought 10 seats this past year but typically it's been around 6. I haven't had much trouble keeping them together. We've moved around to see what viewing angle we like best but also sometimes to get away from annoying fans. 🙂
We don't pick particularly early I don't think but certainly not toward the end of the renewal time period. Maybe you should try to do what others have mentioned and not renew during your slot. Wait and keep checking back.