MShelton wrote: Does that mean if I have 10 machines I am covered for licenses already as long as the machines only have 2 gpus?
You can have more GPUs per machine, if You wish (and able to build) You can have 10 or 20 GPU/machine..
As Beppe pointed, it makes sense to use built in Network render feature, but You can have two licenses: one for workstation, other for network rendering master + multiple nodes (as single license would cover all of those) - this way You would have a bit of flexibility and and also, Your main workstation would be clear for work and tweaks.
Last thing to advise, get dongle, at least for one of those licenses that are mission critical, so lack of internet would not stop Your render job - it's a simple offline license option, that You update once every few month and if internet is down You have no worries - Your render farm would keep on running as it should (same could be said for UPS to those workstation and render nodes).