Really interesting build!
I'd love some more build details on your centrifuge!
I messed around a lot with wvo in the early 2000's. I want to echo what others have said: It's much harder to find in 2016 then it was in 2002. The renderers/disposal companies and restaurants changed their business model up, likely in response to us dirty weirdos offering restaurants free pick up of used oil. I'd love to hear how your on-the-road filtering goes. I'll probably hook a second tank up in my bus eventually.
FWIW, I used a dieselcraft centrifuge to flter. I had a wire mesh filter on my collection sucker, then did ~5 passes with the centrifuge. I checked how gunky the thing got after one pass and made adjustments based on that. Also, have to be there when the 'fuge spins down to catch the gunky stuff that tries to fall out on spindown. After the 'fuge, I used a 2 micron absolute on the transfer pump to the fuel tank, and used a pressure gauge on that to see how well the filtering had done. When I really had the system down, the 2 micron final filter would last months and months.
On steel tanks: they can allow a vo "skin" to form inside via some mechanism I never understood. I still used one, but had to have a way to clean it out. The other option is to make an aluminum tank; those don't seem to have this problem, but do have a problem of their own, ie, triple cost of steel, maybe more.
I used hose-in-hose coolant heated fuel lines. I imagine this is even more important on the long fuel line runs on a bus!
Finally, and most importantly: You will spill VO one day! No question. It'll happen. Plan you VO storage with this in mind. I see all those cubies on the floor, and I remember the smell and feel of trying to mop up warm used VO... a redundant spill catch pan is SO INCREDIBLY VITAL!
Good luck, keep us posted!