General :: File / Folder Permissions And Groups On Linux With Apache?

I'm trying to learn about permissions on linux webserver with apache.Some clues to the system: The server I have to play around with is Fedora based. Apache runs as apache:apache. To allow for e.g. php to write to a file the file needs to be chmod 777. 755 is not sufficiant.What I'm wondering is basically how set up permissions like they should be on e.g. a "shared web host".My main problem is that if I set a permission so that one user cannot access anothers home folder, then apache can't read from the public_html folder either.

To keep the users out I need to set chmod 700. But to let apache to read I need to have at least execute on world,so a 701 basically works, but won't let some users in.So I'm really stuck on what to do. Have been concidering adding the apache user to the frous grours
below to avoid having to add the world execute flag, but is that a bad thing? Should it be the other way around, the users in the groups below should also be in the apache group?I was aiming at having 4 groups:

1. webapp: same as dev_int, but is the only one that can go inside the webapp/live folder to e.g. do an update from the repo.

2. dev_int: can read,write and execute everything in the "web root", including the two below, but nothing outside of the web root

3. dev_ext: can read write and execute in all client folders, but cannot access anything outside of the webapp root

4. clientsBasic ftp accounts. Has a home folder with a public_html, but cannot access any other home folders