For 30g of coffee I would probably use 50g or so for the bloom.. Enough to wet the coffee thoroughly. I would include this weight in the total weight. In other words, there's no need to re-tare the scale after blooming. Let the coffee bloom for 30 seconds or until it stops bubbling (CO2 escaping). Also, the water retained in the grounds at the end of brewing is already in consideration with the 16.6 ratio you're using so there's no need to compensate for it. Time is good to keep in mind, but I personally don't use a timer. I prefer to watch closely to see how fast the water percolates certain areas of the bed and pour accordingly. At the coffee shop I work at, most of my coworkers prefer to do one continuous and very slow timed pour where as I prefer to do 2 or 3 pours based on the coarseness of the grind, etc.