Not to get all nerdy, but there's a couple missing variables: water temperature and evenness of extraction. Water temperature is pretty easy. For light roasts brew hot, almost boiling. For dark, brew a little cooler, maybe 88-90 degrees. Evenness is really the key. Now depending on your method you can do all sorts of rituals whether it's using some super thin needles to rake your coffee in your portafilter to remove clumps (WDT) or pouring careful concentric circles into your V60. But the easiest answer is to eliminate the variable by brewing with immersion. I'm a huge fan of the Hario Switch, but you could just as easily use an Aeropress, a Clever brewer or a good old french press. If you do immersion, steep for a reasonable amount of time (2 minutes on a Switch works well) and adjust the grind according to your taste buds (too bitter -> grind coarser, too sour -> grind finer), you'll be in the ballpark of good coffee very quickly.