I think this is good research that you are conducting. I started off the same way, and spent 6 months just on MA's, between 6-10 hours a day.
I hope you find some of this stuff useful:
1. Video of Karen SuperTrader - she is the reason I got into indices, - https://www.youtube.com/watch?v=cXy9HoWX0es - she trades indicies - I think you might find her comments interesting
2. Good tool to run quick test to test the efficacy of the golden cross MA's - http://www.movingaveragebacktest.com/?symbol=SPX500&capital=30000&long=true&short=true&years=1&ma=30,50. I hope and think that TV will soon offer use something similar to run back tests. I found that just looking at charts can be misleading.
Personally I found that standard MA's meaning SMA has significant lag built in, and while often giving good long entries, it mostly exits very late. Even HMA, WMA, and EMA which are better in some respects suffer from this problem, because they take too much data, which is not fresh into the account.
There is a better way. Usually indices, will no go up or drop more than 3% per day for around 96% of the time. Meaning the trade between a -3% to +3% band MOST of the time. You can run your own tests in excel to check this. This information is useful, because it means that instead of using long MA's with stale data, we could instead use much shorter time frames, and discount the price MA with -3%.
For example in test I have used an indicator I developed. Chris was kind enough to code it, the guy is a legend.
This is the long only indicator, on the same ticker as you used above:
This is the short only indicator, again based on the the same chart.
I hope that gives something useful to look at,