All the above sounds about right to me with a few exceptions. Brushed components might be cheaper to purchase, but they don't last as long and don't have as much power. Trying to find a brushed tail motor that won't burn out but is small enough not to add too much weight is difficult. The other thing you must do no matter which type of motors you use is to disable the Battery Eliminator Circuit on one of the ESCs. The BEC supplies power TO the receiver. You don't want the tail's ESC to supply power TO the gyro and then TO the receiver, so to disable it you need to remove the red wire from the servo connector that plugs into the gyro. Be sure to cover the wire so it doesn't short against anything.

Here's some directions to follow from Helimax:
http://manuals.hobbico.com/hmx/hmxe04-gyro-manual.pdf