it would probably be benificial to order/buy the factory repair manuals for both the chassis and engine so that you know what systems are there and how they are supposed to work
use after market filters/water seperators,RACOR or GOLDENROD are popular brands, for your wvo system, they have removeable transparent bowls with drains that makes checking and serviceing them easy,
Install an electric pump at the tank to push your grease thru the system, it can also be used to bleed/purge air from the lines and filters.
don't forget to run a seperate return line (low pressure) for the wvo to keep from contaminating your diesel tank, it is necessary to circulate fuel thru the system to cool and lubricate the injectors.
try to find a fuel tank switching solenoid/valve that has provisions for both supply and return, NO scratch that you want to switch fuel in and then have time to flush the wvo out of the system before you switch return lines, seperate valves.
good luck and keep us posted