Check Valve it
Yes on electric supply and filter on the diesel side for the OBS trucks.
I bought a used GFS system with that Pollack valve, a booster fuel pump, Racor, Hot fox, tri-hose HOH and a huge poly mess in the tank. I think the guy I bought it from ruined his truck from poly running through his diesel side, hence the screamin deal I got from him (I'm sure he got a good laugh out of selling it to me, ignorance can be a dangerous thing in the WVO world). He told me all about tieing in behind the diesel pump, etc etc. Luckily I half listened to him and did my own research.
After a ton of reading around here and other forums, I think you may find that using your existing Diesel side with that little booster pump and pollack valve is not the right way to go for our high pressure powerstrokes. Keeping the two systems separate will be the way to go, unless you live in Florida and have super clean oil as you will always have unused VO in your diesel filter making for tough starts in the cold.
The only things I used from the GFS system were the 100gal split tank, the heated Racor, the hot fox and a few misc fittings and clamps. I didn't even use the Tri-hose that came with it because it had blue Parker hose that wasn't rated for our temps or pressures. GFS could use that hose because they come in behind the diesel pump on the vacuum side.
I'm sure this is not what you wanted to hear, neither did I, but I am happy so far having the redundancy in the systems and the ability to get home if there is a VO issue or as some have had to do, use VO to get home when there is a diesel issue.
I've only got 4k on VO though, listen or read the posts of the guys a ton of miles on veg. They all have split-heated systems or better yet the Vegistroke V3.
02 F350, 227k, cclb, 203 deg, coolant filter, stancor GPR
FN74/SkySki/Leon inspired system, 100gal split tank GFS (repurposed) tank, hot fox, 20 plate FPHE, check valved, purge, HOH, heated Racor 1000FH and 23amp FASS pump.