I have backtested a strategy on two different symbols. For both of them time frame is different(I backtested them one after the other). One trades on X min time frame and the other on Y min time frame. I wanted to run a simulation on how this would go when traded together. I couldn't find a direct method of doing so. So, what I did was I took the % returns from Symbol 1 and the % returns from Symbol 2. Copied them together in an excel file. And ran a Monte Carlo Simulation of them together(So, the assumption is that they retain the position sizing method in their original testing and in the Monte Carlo the both trade at 1:1 allocation on a portfolio level). Can this method be an alternative to backtesting them together(which could be a real pain in the behind if we were to use AmiBroker/NinjaTrader)? Can the results of MCSim be considered for any decision making?
No alternative. MC in trading is useless. Ask those who were doing mean reversion during the 2008 crash. Try to find them in their farms in Oregon. They also relied on stuff like MC simulation. For example MC simulation destroys auto-correlation. The results are misleading.