I understand wanting to stick with it until you get it right. Good luck doing so.
As to KT being easy, well, I'm probably not the best one to ask. I think it is easy but I only ever do very basic stuff and I usually do essentially the same thing every time. These renders only took a few minutes to complete and other than making some adjustments to the material using a preset, I didn't really do anything special. The background in the last one is just your concrete material inserted as the background in KT. A few seconds to do and I think it really improved the way the ring looks.
Keep plugging away and you'll have it.
