@daphne1 So 80% of 105 means 84m2 per floor, but the design will need some hallways and stairs on each level, so take 10m2 off per floor for that (ballpark, and the 4th/5th floors could be less).
So 84 - 10 = 74m2 per floor, divide by 2 apts/floor for ~37m2 per 'one bedroom' apartment. Also...