when I did mine I used a NAPA filter head with 5 micron cartridge.It had 2 inputs,and 2 outputs.I blocked off one output,ran from other output to heat exchanger,then into lift pump.I disconnected cigar hose and used a shut off valve with a three way,and ran hose back to other filter input.This way I could loop my fuel.I had a 2 way common garden hose valve that conncted to either veg tank,or diesel tank.I ran short hose into a 12 psi electric fuel pump to push either fuel to engine.Thiis took care of bleeding problems.I would switch back to diesel for a few miles when parking over night.

__________________
1999 w140, quit voting to old, and to old to fight, a god damned veteran