One for the clutch and one for the PRVR. Removing the clutch tank means you won't have vacuum assist when pressing the pedal to start the engine but if you can live with a heavier clutch or move the neutral switch it's no big deal. PRVR can be ditched anyway, IIRC it's just there to help with fuel vaporization in the line after restarting a hot engine and I've never heard of any problems with deleting the whole thing. All it does is remove vacuum to the fuel pressure regulator when starting to up the line pressure.