2 stroke ringed vs. abc engine.
nitro content to run.
lower in one higher inthe other

This all depends on the engine you have or are thinking about. What are you looking at?

Nitro content is limited by engine compression. The higher the compression, the less nitro you can run. Nitro is more expensive in Europe, which is why European engines generally have higher compression ratios.

ABC and ringed are just two methods of achieving engine compression, and therefore shouldn't respond too differently to the same nitro level if the compression ratio is equal.