Let me know if you think I have stalled in my progression and need to start utilising the rudder to continue on the path to becomming an expert RC pilot.
Yep. So here's your assignment. Do a slow, large loop - say 100 ft diameter - over the runway in a cross-wind situation of at least 10 mph. Simple maneuver.
See how you do without rudder. Then see how long it takes you to get a good one staying in the center-line of the runway for the whole entry, loop and exit.
Next assignment is landing down the center-line of the runway in a cross wind ("crabbing"). When done well this is the most beautiful of landings.
Both of these take rudder finesse. Done properly it's just a smooth path that would leave a non-pilot wondering why the old timers are saying "nice job" among themselves.