Should I use weight or volume when measuring doses? My pour over/drip coffee pot recommends that I measure 10-12g of coffee per person whilst my grinder has markings to indicate whether the ground amount is for 1 or 2 cups. I notice that darker roasts being slightly more oily seem to weigh more and therefore the volume is less compared to a lighter roast so the question is which method of measuring is correct?

I understand that taste is subjective and I have been using 11g so far but given the variability in weight and volume is there a correct method which perhaps can be adjusted for different roast types?
In cooking in general weighting dry ingredients would be much more precise and give you greater control over your variables.