With such a small implementation, I'd personally recommend sticking with using teh SEPM to distribute updates to your clients.
Symantec recommendations regarding the LUA say:
LUA is not recommended for the following scenarios:
- Updating any amount of clients through LUA instead of through a management server like Symantec Endpoint Protection Manager (SEPM)
- Updating environments with less than 1700 unmanaged clients sharing the same Internet connection
- Updating clients across WAN links
http://www.symantec.com/docs/TECH93409
Along with further descriptions of when to use the LUA in the below article:
http://www.symantec.com/docs/TECH154896