I send up a silent prayer to cookbook authors that include weights. That's why I
was able to make that 3 layer/3 filling cake in 3 hours. Payard included the weight, so I just put the KA bowl on the scale and dumped. So Much Quicker!
I also keep a running list with the empty weights of my key baking bowls. That way--when the batter is done--I stick the whole thing on the scale and get a TOTAL weight. Then I subtract the weight of my bowl (for example, my 5 QT metal KA bowl is ~800 grams) and divide the remaining amount by the number of pans I'll be using. Put each pan on the scale, tare it (set it back to zero) and add the exact amount of batter for each pan.
For example: total weight (batter/bowl) weighs 2000 grams. Subtract 800 for the KA bowl and that leaves 1200 grams of batter. If I'm using 2 pans, each pan gets 600 grams of batter. If I'm using 3 pans, each pan will get 400 grams of batter.