This is correct, but you’ve got the examples wrong. It is the other way around
The needed permission is the one that resists a kick. Meaning this need to be 50 and the kick power need to be 50 or above.
Regarding your A1, A2 and A3 channels you may check out this post. If correctly set up this can be achieved by using channel groups, which only apply when the user tries to join the channel or when he is in the channel with the corresponding group. You would then need to manually move them into the channel and assign them the new group, that allows them to join the channel.
If you need any help regarding that, please post over there
You currently can not copy / apply settings for channels without using an automated system like a bot or Server Query.