Another thing you can try is using larger diameter fuel lines. Your stock pump should be able to pull the fuel, unless it is really thick or really dirty. Maybe your lift pump is worn out? And I think most WVO filters need to be under suction, if you pressurize one side of the filter, you will not get very good water seperation.

__________________
87 300D - Running on Veggie oil; 260,000 plus miles; Original #14 head