I do the maths when I practice things vs the computer, in real games I just pay atention to the build orders and if i have spare time i check the "econonic" minimap to see how are my vills splitted, other than that I play by the eye. You cant be too picky with the maths anyway because vills get stuck and stuff pretty often or enemy forces you to garrison or whatever so at the end they serve more as a reference than as an iron written rule
we never developed it btw.
every expert i spoke with (dogao, viper, spring, dreams, cerberus etc) say "i do it by feel" and "it just feels right to move vills" etc
i'm becoming like this too, but for me it's still a problem. i still have to think about it, check my gold, wood, food stockpiles and how fast they are building up, etc.
for the experts that have been playing for a long time on a top level... they just look at the lumber camp and KNOW (because they saw it 100's of times before) if they need more or less. it really is a "feeling"