fuel is made up of 3 parts.....oil, to lube and carry away heat,.... methol alcohol, which is the real fuel, it's what we burn...nitro which acts as an oxidizer to help the burn.....
Nitro will cause the burn to be a little hotter but not enough to notice if your engine is properly tuned....and wilkl usually give you a better idle.....As said above some engines by brand not by a particular engine likes a lower nitro content.
So to answer your question there is no need to change nitro content.....but once the engine is broke in you need to lean out the mixture for more power...but do not run too lean