[theamk]

This is like 4 questions in one post - 24V constant voltage strips, addressable LEDs with controllers next to them, remote controllers for addressable LEDs, diffuser channels. Each one is different. And for most of the time, you don't want "rules of thumb", you want basic EE knowledge:

You know the voltage drop you can afford and the max power of your lights. And you should also know the internal resistance of the lights (or you can measure it if you don't know). This gives you the power injection rules.

For things like "resistor values" and "signal integrity", you need to know specific cable setup you have to match impedance. Or get a scope and try different values yourself - you don't need anything fancy, cheap $150 scopes work just fine. Or just put your controller next to first light, most lights regenerate signals, so only distance to first light matters, not overall strip.

Your "repeatable checklist" must have specific models of lights and cables and connectors to be useful.