I personally would just apply regardless of the 6 month rule (if there is one). It could be another year before they open another window after this one closes for all we know. They need pilots, and if they want to wait the full 6 months to call you again, let them make that decision. At least you’ll have your application on file, and they like to see that you’re interested by applying in every window. In my opinion you’re not going to get dinged for not waiting the full 6 months.