NP, in "Overscan Area" > "Set overscan area", change 0,0,0,0 to something like 40,22,40,23. FYI, the numbers seem to be pixels of overscan, one for each edge. The first number is the left edge, second is top, third is right, fourth is bottom.
After you change the overscan area, drop down to "MISC" > "Set on boot" and check that box. Now the overscan stays adjusted when you reboot. However, even though you made the change persistant, the UI Tuner control panel, when you open it, doesn't display your change, but the change is there.