day tank

Hello! I am trying to figure out how to vent a diesel day tank for my new diesel cabin heater. The tank is mounted inside the on a bulkhead on the beam of this Catalina 30 (see attached photo) and will be filled via transfer pump from the main tank. I am not familiar with thru-deck hardware...

Has any of you C30 owners set up a day tank to gravity feed a heater? I have the Dickinson Newport diesel and am thinking about running the high pressure fuel pump to it to prevent the pump running every now and again. Where did you put your tank? Above the dresser? Above the settee? My heater...