Multicharts.net Algorithm

I am interested in having a simple algorithm coded for automatic/robot trading on Multicharts.net. The algorithm would create a long position when with the 5-period exponential moving average (EMA) crosses ABOVE the 20-period exponential moving average (EMA), upon the next candlestick bar close. The long position would be closed when the 5-period EMA crosses BELOW the 20-period EMA, and, simultaneously, a short position would be created. The short position would be closed when the 5-period EMA again crosses ABOVE the 20-period EMA, and the cycle would continue. However, I need to be able to modify the times. For instance, I need to be able to tell the algorithm to trade only during certain hours. I also need to be able to modify the size of the trade. I'll be using this to trade mostly mini futures.