RE: digital newbie help
It is very helpful to have a matchbox when you have to use multiple servos on one surface to match the servos, or in the event you are out of channels in the radio and/or need to reverse one of the servos from that channel. Also the matchbox allows you to use an additional battery on the matchbox in the event that you need additional power distribution.
I would run anywhere from a 1500 to a 2700 pack depending on the number of servos being used.
The 8101 is an excellent servo and works great for many applications, however it will doesn't have the centering and precision possible of digital servos.