[suicideneil]

Bearing in mind those escs are plane/heli items, with poor brakes and no reverse (more like a handbrake, but adjusting the throttle epa may help), I think you will only need one BEC. The escs will need to be connected ot the Rx via a Y-lead, and the BEC should plug into the circuit between the single leg of the Y, and the Rx, then connect it to one of the running batts. You should use a seperate LVC too ideally, connected to the battery supplying the BEC. That way when that cell hits LVC first, the whole system will shut down.