IF I had the money I would go with the li- mag batt as you can charge it in the plane and I would put the switch an charge plug on the batt side. get a cheap digtal volt meter an a 10 ohm resistor from radio shack to check the batt voltage.
As far as rx's I am really impress with the berg RX. Here not so long ago I turned on my plane and turned on the tx that was on ch 40 then I turned on another tx that was on ch 40 an the plane responded on to the tx that was turned on with the plane so then I tried flying th plane so I turned on the tx then the plane an took off Then I had a friend turn on my other tx I could tell that something wasn't right but I still had control off the plane. btw the plane was a christen eagle