Great explanation. Sadly I won't have prior information about the stiffness. But I know that I will use a 2.2kw Spindle which can handle 1/2" shanks.
My 300m comes because my table is 4 times longer(1,2m - 1m) x 4m. Because it is my first cnc I am building. I was expecting an uneven table with 3mm height difference. But that's just a guessed number. So with a 2" tool and 1mm cut depth I assumed 20 x 4m x 3 rounds -> 240m. But as you said you are going a few tenth of a milimeter it will even be more runs.