Well, you are definitely narrowing the list of potential issues so that is good.

The problem I see, is you are doing too many things that most of the greasers would say are "no-no's." Maybe you have resolved the issue of the 2 micron filter, but you are going to run into more of the same problems with that fuel system because of the PO's design.

Here are some of the "no-no's:" (for lack of a better term)

1.) using the stock fuel filter for WVO
2.) using mild steel tank
3.) using the stock fuel pump
3.) not using a heated filter head
4.) running a blend.
5.) using part or some of the steel stock fuel lines

Even if you fixed or replaced all the fuel hoses (with EDPM that's a great upgrade btw ), replaced the 2 micron filter, replaced the fuel pump, cleaned the steel tank, etc etc.... , X number of miles down the road, you will be back at the point you are now. Maybe that is ok with you, and cleaning or replacing the 2 micron filter is not a problem for your driving patterns.

But if you want to make this system work long term, you might need to scrap the PO's old design and put the truck back to stock until you can do a full 2-tank conversion. You'd want to have a separate aluminum tank (probably with a heated fuel pickup like a hotfox or aluminum hose coil), dedicated veg fuel pump, heated aluminum HOH/TOT/TIH fuel lines, nickel-plated (not copper) 20-40 plate FPHE, heated filter head like this, aluminum fittings, and sturdy not plastic selector valves like Hydroforce or WVO designs stuff.

Not trying to cramp your style, but I've seen too many guys get a Diesel to do a WVO conversion, just to be tracking down endless fuel-related problems. Most of them just gave up on the whole process. Some said screw it, replaced the whole system and most are running grease to this day.