That is correct, I have a real money account where I trade with a 1k position size and a paper account where I trade with a 20k position size.
Here's the problem with your line of thinking. Trading is very much similar to competitive sports. There are only so many systematic rules you can follow but you are still a human being and it takes a combination of skill, talent, experience, psychology, etc to win in addition to rules. In other words. Even with the perfect system. You can still lose if you have poor psychology. Like others have said. Sim trading is useless because there is no emotion. A small account may help as there will be some emotion. But when sizing up the emotional stress will also size up. Food for thoughts.