HeLa seeding density should work. half million per well (if u want to do short term treatments on the following day) . 1/4 to 1/5 split ratio also worked in my hands.

Hope it helps

Thank you very mucj! I need to plate 6 milion of cells for RNA extraction, where could i plate this cell number?

If u follow HeLa numbers (can refer to HIPERFECT handbook Qiagen), then seeding around 2million in 10cm plate could give 6 million on confluency.

If u need for realtime 6well is good enough.

Good Luck