After search and study, I found answer of my questions. I am sure this answers are useful for you.
DMEM is suitable medium for transfecting. Do not use RPMI culture medium.
Do not use buffered DMEM with Hepes solution.
Considering to my work experience, HEPES in media have effect in transfect efficiency. After 16 hours from transfection, cells are detached from plate.
I am using calcium phosphate method for my transfection. And I using only MEM medium to culture and grow my cells. They behave fine with it. And transfection rate is around 70-80%.