Yes after doing true arbitrage between different exchanges trading cryptocurrencies it has gotten me back in the mood to figure out a stable process of trading using my general theory. And yes Excel is the better way to trade it. If you try to trade visually you may win or loose depending on when it repaints, but that is not safe trading. That is gambling.
Im testing out a way right now which shows much more promise than the original strategy, which is maybe what you are currently doing. However, I am using the historical 1 min data starting with 1 months worth and then slowly adding on to it each day.
I put the historical data in excel, find the mean and standard deviation of both currency pairs and then I "Standardize" the data set and plot the two charts together as they now have the same standardized reference, This way shows to be very stable and the "chart repaint" does occur but since you are dealing with such large data sets every time you add new data it only changes the "average" by a minuscule amount allowing you to more accurately see the gaps