Yes, sure I used it, and so did many others. What is more, I tried RCP in almost every game since I tasted that rank fruit. Granted, I prefer pangaea/continents. But even if it's not possible to establish fully completed rings, it's a powerful corruption killer when you minimize the number of city ranks. For the "starting at the coast" reason, I sometimes used the FP as RCP center and moved my Palace later to have a second RCP core. And then, the rank exploit appears: if this newly established capital was very far away and somewhat seperated from any other city - there was this income boost because of all these (suddenly) rank one cities around your FP (look at my first post in this thread), just like Qitai discribed. Well, you don't need RCP around your FP to exploit the rank system, but I did not know that by that time and payed attention to FP distances when founding cities. I used to guess the reason of that income boost was a srew up in the rank system due to having FP near palace: cities had discrete distances to FP, but possibly not to palace, thus resulting in a higher number of ranks. Well, I know better now.