RE: Rhino 4900
The feedback I received is that the Nano packs like to puff earlier (after 20-30 flights from brand new) than the original Turnigy ones. Do not know if it is a characteristic of the Nano packs or not. I have multiple Turnigy packs (original) and pretty happy about their performance. The only drawback is the weight penalty at out 2 lb 14-15oz.
A pack with 4+6 25c configuration will work well as the ESC does not care how the 10s is physically configured. The only drawback is that you need to re-solder the balance connectors if your charger is good for 5s.