Khums is 20% of the saving and half goes to your marja or his representative or Masjid or centre who has the permission from marja to collect the khums . It will not go to every maulana only who has permission to collect.
Half goes to poor and practicing Syeds. If anybody from your relatives you give preference to them it is totally up to you how much of the share you are giving all based on amount and need.
2- if nothing added then khums will not applied .