The problem with that idea is that the market behavior changes from one year to the next. So what worked one year or even two years hence, does not work for the next one year or two years ahead. Trust me on this. I have the losses to prove it.
If you are a beginner without any live trading experience, the demo accounts are suitable to learn and understand the forex market. I started trading with a micro account after three months of demo trading and used a micro account to avoid high capital and risk.
Use a demo to test your trading system. The live market will make you money and it is very dynamic. So, take small risks and go for micro accounts once you develop a trading system.
the demo is a master place to practice well , i trade here and always practice all my trading strategies to see the performance how it works.
besides using all trading strategies it is more appropriate to use high leverage in demo to see its real character.
If you want to understand mechanics of leverage (the size of position you can enter, pip value, maintenance margin) then yes you should thoroughly examine its feature. However I would advice to steer clear from using high leverage on live account because experience can be really painful if price spike occurs when you are in position. Consequences are unpredictable.
demo is really knowledge if you can focus on there. but without real money that is really a challenging issue to continue it.
micro account is effective than demo account , but sometimes micro account can make beginners greedy and emotional.