Speaking as a Permission Giver, I'd advise you to wait longer than a month from now before trying for Permission. Based on the questions you've been asking, I don't think you've really grokked the nature of the PPC yet, and I would personally hesitate to grant you Permission until I see that understanding improve.

I recommend that you spend plenty of time reading (more? any?) spin-offs before you decide you're ready to dive in. You may also wish to avail yourself of the Permission Self-Check and use your level of comfort in answering the questions in it as a rubric for how ready you are to be writing PPC stories.

If you need spin-off recommendations, I have some! But keep in mind that most of those are older ones (because I am old), and some things have changed since they were written, such as how we define a Mary Sue and what we find acceptable to say about fanfic authors in a mission, so don't limit yourself to that list, either. Check out what's been published most recently, too—and give some feedback if the story is on AO3 or somewhere you can do that. That's a great way to get yourself in good standing with the community. {= )

~Neshomeh

I can beta for you if you want.