OS X Server :: AFP Share For Teachers/students?

I am fairly new to OS X server and server administration in general so bear with me

My goal is to setup a share point that will support teacher shares with assignment upload and download folders in each share. I would like to automount these shares upon login so they show up on the desktop.

Currently the teachers have open directory accounts with a Managed preference login item that mounts the share point.

The students are using local accounts in the labs and I've automounted a share for them using a local login item with an apple script that calls a mount_afp command using a dummy account in open directory so I don't have to use guest access.

Currently, I'm just using POSIX permissions to keep things simple as I've ran into disappearing folders using ACL's with Tiger (anyone else seen this??).

So a few questions:

1) Is this an ok way to do this? Are there better ways?

2) Is it a good idea to have a logout hook to remove the mount directory when each user logs out?

3) Will my dual 1.8 Ghz server with 1.5 GB of RAM and a 200Mb (aggregate) network connection be able to support approx 50 static AFP connections? Thinking about taking the idle time down really low...heard in OSX 10.3+ that when connection is idle it unmounts and when user clicks share it will re-mount it, sort of making it dynamic it sounds like.