Using Two Receiver Batteries
I meant to include this in my last post, but forgot.
The person that did the test ran 10amps for a few minutes. If I remember correctly, it was to one set of plus-minus pins on the receiver, and out another set of pins. The person that ran the 20amp test, only ran the 20amps for a number of seconds (10 or 15 I think).
Another data point. A lot of the giant scale pilots flying the 40% or so sized airplanes also use voltage regulators when using Lithium batteries. These regulators are typically rated at 10amps maximum current. Its safe to say then that a 10amp load isn't common, or at least the maximum peak current, and not sustained, or it would have shown up in flight tests as poor performance. The 10amps is also spread across several connectors to the servos, but comes from one or two sets of pins from the batteries depending on a single or dual battery setup.
When my rudder servo failed on my Giles, the stalled servo was measured as pulling just over an amp. 9 stalled servos would pull 9amps sustained. 4 servos running normally will hardly pull an amp total, and all 4 stalled would still only pull 4amp. Still within reasons based on demonstrated usage.
Hope this all helps.