If I want to do an RTA of a full world what are the rules? -Can i start on an old save file thats already done all the levels so I won't have to watch cutscenes or do I have to start fresh and include cutscenes etc

play on a new save file :) you can save every world in emulator so its not big deal. timing starts when you enter the first level and timing ends when you beat the last levelin the world.

Thank you