I have a child at three of the schools mentioned. Skinners does not have a catchment area, it is superselective.
Twgsb does have one but it's very big (see website, 11plus forum or Kent advice already mentioned). That is pass only for admission.
As others have said, Judd has a lower entrance score for its in catchment pupils, but you need more than a pass to get in. They publish previous year entrance scores on their website including waiting list ones.
TOGs has inner and outer scores.
TWGGS is pass only but very difficult to get in to unless you live very close, last year there were tape measures out to check distances again.
Weald is pass only but has a pretty big catchment, also in SEVENOAKS now.
It is complicated, for instance despite many posters stating that Kent is entirely selective, there are pockets that are not.
If you lived in Paddock wood for instance, you go to Mascalls comprehensive, you wouldn't get Weald even if you passed, despite only being a couple of miles away.
You could however go to TOGs which is pretty much next door as an out of catchment applicant.