Your implicit premise is that reality will comport to the right formula or algorithm (instead of *searching*for* the right math to match reality de'jure), and in that, you are completely screwed.
YOU must instead search for the right math to match the reality before you, AND you must keep a constant eye on your results, because ALL such results are preliminary. Always.
So, *ignore* what "everybody else" does, because few actually apply any sort of 'science' to their numbers. Perhaps 1-in-25 who read this, have ever actually modified the 12-26-9 settings on their MACD -- fewer than 1-in-100 have ever actually bothered themselves to know what those settings mean. BUT THE MAJORITY will moan about how "the MACD doesn't work." Do you want to join them?
Work some numbers. Figure out what an SMA of various look-backs does. Figure out what an EMA does. LOOK AT YOUR UNDERLYING. Which *should* match better? Work some more numbers. Which *does* match better? THAT'S THE ONE YOU WANT, keeping in mind the first bit: all such results are preliminary, subject to check, "YMMV" etc etc.
And at that point, when idiots moan about technical studies 'not working', you'll know what homework they have not done, ever, in their past.