putting a plenum on my car and have stuff all room.

currently running a pajero master. have ran an r32 master before.
anyone have any ideas on a smaller resovior. i think r33 is pretty small.

other option is to go external resovior. any thoughts would be good.
prefer not to go external as i already have one for the clutch. unless i run one big one for brakes and clutch?
room we working with.