I installed a Plantdrive system(www.plantdrive.com) in my 87 6.9 f250. It consists of a Hotfox coolant-heated (CH) tank pickup tube, a Vormax CH water separater/filter, a CH flat plate heat exchanger(FPHE) and a 30A 12V Vegtherm heater.
From my 5/8" heater line T my 1/2" coolant line runs to the aux tank-filter-FPHE-heater return.
My insulated filter/water separater is mounted on the passenger-side frame rail opposite the tank. The FPHE is in the engine compartment passenger-side, aft of the battery. I replumbed the lift pump so it pulls through the stock fuel filter or svo filter.
I'm using a looped return for the SVO, but the diesel return line was reconfigured by switching the driver-side rear return line ( the one that goes back to the tank) with the front one. This made for a shorter line to my 3 way return solenoid switch and a more convenient place to make the connection and less svo going to the diesel tank on switchover.
I'm not clear on what you mean by the dist pump or how the backflush works? I'd like to add an electric pump for the SVO, but don't know if I could still use the lift pump for my diesel. Hope this helps, but ask me for more details if needed.
Mike