With a return fuel line a little air in the lines really isn't a problem. I just replumbed my system and added a switch valve for running on WVO. Didn't bleed anything despite having a little air in the diesel line. I then added oil to my 2nd tank.. and literally sucked the oil from the trunk and filled my Racor filter without bleeding. That said I only had the oil tank switched on for about 20 second intervals till I had cleared the air from the lines. The engine didn't sputter at all.

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'84 300CD Turbo 132k (Anthracite Grey) - WVO - My daily driver - Recently named coo-coo-coupe by my daughter.
'84 300D Turbo 240k (Anthracite Grey) - Garage Queen
'83 300D Turbo 220k (Orient Red) - WVO - Wifes daily driver

I'm not a certified mechanic, but I did stay at a HolidayInn Express last night.