If you are getting a better TX battery, I highly
recommend an Eneloop NiCad, made by Sanyo. They are plug and charger compatible; just stick it in and use the stock Aurora charger. They last for weeks with minimal discharge; can be left plugged in without overcharging. They don't have high C, but we don't need it for the TX.
Here are two sources.
This one, at least, has the proper plug already on it.
These are both 2000 mAh, so you get a bit less run time than a LiPo, but the increased safety and decreased hassle are worth it, hands down. Also that it STAYS charged, when it is not in use.