Layout Pages and Security

Working on my application today, hacking my way through it and I am trying to understand how I should have security setup. I have a admin dashboard were a true admin would log into and create objects such as events, classes out items in events and classes. These people will have an admin role an access the admin dashboard through /wap-admin. I also have users which they will access through there “account” through the frontend but I want to lock down permissions on the user dashboard will be able to be accessed if a user is logged in.

I have 3 layout pages
main - no security
user - logged in user
admin - administrator

Should I just set security per partial page or should I continue to have several layout pages with security set there?

Should the security identifier carry across layout types?

Thanks