Internal and external balance.

Marcohotrod said
the weight of the oil? please tell how this guru knows how much oil is on- the crank, rods, pistons etc.

You don't know how much oil is on anything at any given time. For wet sump engines with bores of 4 inches I use 4 grams TOTAL. When you get up to 4.4 bores I add a gram. I also change the percentage of balance as the rod to stroke ratio goes down.