Personally I would start with the defaults, and modify them if you feel it necessary - generally speaking the defaults are a good starting point.
The one big, big thing to avoid though is deploying large numbers of sensors at once. The first time a sensor communicates with ePO the server needs to generate a key pair, which is a very CPU-intensive task. If a lot of sensors try this at the same time it can have a very marked performance impact on the ePO server. Instead I'd deploy the sensors in batches - say a 50 at a time, and monitor the ePO server as they come online to make sure you're not impacted.