Party / Party
To align the party list to the bottom, first select System from the main menu, then open the HUD Layout menu. From the Current UI Element dropdown menu, select party list, then use the neighboring gear icon button to access UI Element Settings.
From the UI Element Settings menu, check the box next to "Align List to Bottom."
This option will eliminate blank space on the list even with smaller parties.
Align List to Bottom: Off
Align List to Bottom: On