Every coffee has a correct dose, every shot time has another correct dose, every machine, coffee, time, volume has a correct dose. The dose changes as each variable in the equation changes. There is no one right dose for a coffee. Coffee X in my machine, in my basket, in my grinder with my taste preferences will be different than yours. Most roasters will give a general guideline as a starting point but again, that is ideal flavour profile for their roaster in their machine on their grinder using their baskets and water (yes even the water will make a difference).

You just have to find a starting point and then make changes to dial it into your sweet spot. This is where things like the 'Golden Rule' and 'Als Rule' come into play. They are a generally accepted starting point, then adjust to taste. Nothing short of experience, trial and error will get you there. I will often burn a good pound of coffee just dialling in a blend because I change so many variables to see what the coffee can do. This is also where a log book or notes come in handy. Keep tasting notes so when you go back to a blend, you have a starting point to go back to.

+1

Amen, Dave.