That I know of ePO is free and relatively lightweight... You can easily set it up on a VM with SQL express in a few hours.
An option could be to replicate the dat files from Mcafee.com by doing a mirror task that would copy files from mcafee.com to a local share where you could manually point your devices. This way you would get your dat files updated without any management, policies or event of any type.
ePO is not free other than trial download which expires. So no. No liteweight version.
My bad, we get it as part of our contract so I don't really know the licensing cost just that I can download it with every product that we have procured.
Your best bet is going to be to install EPO on a server and use it only to manage those 60 clients.
Outside of that I might recommend a mirrored repository perhaps setup through a mid package distribution.