1. At what point would a Slave Admin kit be a better choose than a Update Agent?

I have a main site with 200 clients and 5 other remote sites (with limited bandwidth) with no more than 30 clients each. The documentation suggest to install the Admin kit on the main location and Slave Admin servers on each remote location.

I was thinking I could also install just 1 Admin Kit on the main site and work with update agents on each remote site. In my opinion this would make the overall setup a lot easier to understand and monitor. The clients would connect 'locally' for their updates to their Update agent but all other traffic would still go to the main site. I guess the policy updates and tasks do not generate that much of traffic, right?

PS: I do not need to install the packages using AK, we have Altiris for that.

2. Were do I add the Slave server in this kind of setup?

OFFICE1
--WORKSTATIONS
--SERVERS
OFFICE2
--WORKSTATIONS
--SERVERS

I would want the Slave server to be the Admin for Office2 workstations & servers. I added it to the level of OFFICE2, but it appears it does not handle clients located in the subgroups workstation or servers. Do I need to add the same Slave server to every group? Or do I need to create the subgroups on the Slave server?