In reference to the battery. the most efficent way to charge a lipo is to hook it directly to an A/C outlet. but you must find a way to regulate the voltage input and something that will let you know when it is done (take trip to radioshack). because the best way to charge a lipo is with constant current, and the chargers out there do not do that. But with the chargers that are out there it would not hurt to hook your lipo up and charge more. Because the chargers shut off charging when the voltage has drop below a certain number that is programmed into the charger, or a time limit has been reached by the charger. on to the gain question, the gain helps stabilize the tail, and if you turn it down, it will be easier to swing it around with less effort. do it gradually until you get used to it, or to the point where you want it. but you should be able to fly figure 8's regardless. and to use your ouwn transmitter you might have to use the 2 in 1 mixer unit that eflite sells. and then use your own receiver.