Yes, in larger models two batteries are a good idea for redundancy, so if i do it use two batteries they both feed the reciever and ignition.
With the classic two battery setup, one for ignition and one for receiver you have no redundancy for your reciever, and worst case if the reciever battery or switch fails open you have an uncontrolled model with the engine still running. In the single battery and IBEC setup if you have a battery or switch failure the engine at least quits. With dual batteries and switches and IBEC you have a safer setup in my opinion
Pete