A helpful note for the mod info page on bitwise channel encoding would be to point out that you can set C multiple times and it will be summed together to give a resulting channel value. So if you set C8 (channel 4), C2 (channel 2), and C1 (channel 1), the constant combinator will automatically sum them together to give the correct output value of C11 (channels 4, 2, 1).

Another tip: You can also set the platform circuit network to send the current origin and destination (both are the same when arrived) and use decider combinators to change requests based on which planet you're currently at. This is useful for both requesters and providers.

Hello, for the first part, this is already in the documentation, at the end of the channels section.
One can assume that players know that multiple signals of the same type are summed up, since it's vanilla behavior.