First of all, you can use just about any servos with the DX7 DC7000 receiver. And you can use just about any 4.8 - 6 volt battery you like with the RX. And, yes, you can trim the tabs off of the Futaba servo leads and use them. I use Airtronics, Futaba, Hitec, and of course, Spektrum (JR) servos with mine.

The TX battery is the one with the reversed polarity plugs. I remove the battery from my DX7 TX and charge it outside the TX with my field charger. I made up a simple charge cord using the ones you can get from Tower Hobbies (Hobbico Charger Leads) with the banana plugs on one side and the RX plug on the other side, then pull off the covering from the plug. That leaves the pins from the plug exposed. I just plug them into the TX battery, Red to red and black to black and let it go from there. If you leave the battery in the TX, you can charge it overnight using the wall wart charger.

CGr.