My opinion is that in the art/science balance of coffee pourover is weighted heavily towards the art side.
As long as you have a reasonable grind/temp the rest becomes very difficult to explain on paper. A capable pouring kettle gives you a lot of control and you need to feel how you are pouring and learn from experimenting.
So I say start with a grind you think is right, off boil water, a capable pouring device and let the art part take hold.
I couldn't agree more. I used to get all ANALytical about brewing (and roasting for that matter), and have spent years trying to cultivate a more intuitive sensory-based approach. There are enough variables in play that when I get wrapped up trying to precisely control a few of them, I risk missing the forest for the trees. This is probably the most objective description of what I do:
Water: Filtered, mine is fairly soft and has rested for about a day after filtration. I'd estimate 80mg/L (ppm) hardness, based on back when I used to measure it. It works fine, so I don't futz with it.
Grind: Based on the roast level, finer for lighter, coarser for darker, burrs exclusively. Sometimes through the Jolly, sometimes through the Bunn commercial, depending on what else is going on.
Temperature: Electric kettle to boil, wet filter with a splash allowing that rinsate to dribble out, set cone on the insulated pot, add grounds, wet grounds about 15 seconds off the boil, allow to moisten up/bloom for 10 seconds or so. I gradually pour until cone is full (takes about a minute), then I reheat the water to a boil (takes maybe 10-15 seconds), cut power, refilling the cone and keeping 80% full until water used up. This process was established when I measured temperature, with a goal of a 198-203°F extraction environment, but what I do now without even really thinking about it is close enough.
Pour: Turbulence seems to be the key with a pourover, try side by side extractions with a constant pour vs. "all at once" and you'll see over double the extraction in a constant pour. I often use a spoon and do a little stir if I am lazy on the pour to effect the proper extraction.
Ratio: Typically ~80g in a #4 metal or #6 paper cone for a 1.7L ~56oz insulated pot. This is entirely estimated these days, but I bet if I weighed it would be well within 10% I have done it so much. This is below 'gold cup' standard, but usually makes the best (sweetest, that is) coffee IMO. [If I do a single cup pourover, the ratio is often much larger, typically 2.5-3g per ounce of water instead of about 1.5, since the extraction is rarely as efficient and is quicker]
Time: Averages 4 minutes, again, I roll with it.
I usually drink less than half of what is brewed before my next brew (dump the excess), but my process is fairly routine since there is often someone else sharing, in which case it will get used within 15 minutes or so. I have a large excess of coffee so I'm not going to be frugal about it. If I didn't wind up giving away 5#+ a week, I might be tempted to be more thrifty with my coffee, but tossing several half-pots a day is in the noise around here.
