Hello aspirant.

Well as for exam centres, they are completely unpredictable. Exam centres come out for one when they issue the admit card. 

Generally, they give exam centre as near to home as possible, in the same state. Sometimes it could be far also from your home but still most probably exam centres are given in same state. Rest it is very unpredictable. You'll have to wait till you get your admit card. Exam centre will be written on it.