1) Can I charge both TX and RX batteries simultaneously?

***Yes you can. I charge both my plan and 8103 the night before I go fly

2)How do the batteries Cycle? Does it charge first and then discharge?

*** You can hit the discharge button and it will discharge the battery then charge it

3)Is this a Peak Charger or do you have to time it?

*** I believe it is a Peak Charger. I have never timed it

4)Can I damage the batteries if I leave them plugged in too long or not long enough

*** Don't think so. Been using mine for about 5 months. No problems

5)I think it is a overnight charger and if so what is the advantage of using this machine over the wall charger that comes with the radio?

*** It will give you a readout of the charge level or if you discharge then charge it will give you how many milliamps it discharged. The wall charger won't

6) How often should you cycle your batteries?

***Different people will say different times. I have been told about every 6 months.

Hope this helps