-this is the type I'm considering

It's 1.8mx0.9m (5 feet 10 x 2 feet 11) x 2m height (6feet6).
Do I have to separate the sexes? I have 12 finches (5 males, 4 females, 3 sex yet unknown). Ifso, if I divide this aviary in half, it's only 0.9m wide per sex (2 feet 11), is that enough when considering the height?
- What is recommended as flooring. Do I need concrete?
- How does one generally clean the bottom from seed husks and dirt?