I want to backtest a strategy based on Nikkei 225 futures (preferable at the Singapore exchange).
I am using market orders for entry and exit.
Although I now that theoretically market orders for a very liquid instrument should not have any slippage, I have heard that sometimes one does not get executed immediately or other strange things happen.
What is a reasonable amount of points or amount of money to account for slippage and costs for exchange and broker?