Here is what I've learned:
That type of absolute rated filter cartridge, if it's the type from McMaster-Carr
will work fine ONLY if on the suction side of the pump and only if you wipe out the housing real well when changing them, and only if you pull off the liner on the sticky ends so they seal to the filter housing. On the pressure side you can push past them pretty easily. I have also found that for reasonable prices you can get quality diesel spin on cartridge filters and filter heads, many are absolute rated and changing them is easier. My setup is under overhaul at the moment with the plan of installing a spin on filter as my final filter but retaining my 20" absolute filter. There is no such thing as over filtration in my opinion if your pump can pull through them. PM drmiller or search him out on the W85 yahoo users group and he can point you in the right direction for a quality spin on filter and filter head.
I have also learned that my upflow processor while removing a ton of dirt and free water very easily is almost useless at removing emulsified water. In fact straight settling won't do it either, I've had 375 gallons settling for over a month and it's still milky. Zeolite while pricy will suck the water out, RUG will get it out given enough time, but boiling gets it out no problem. I boiled two drums full today, let them boil for a few hours until the temp finally climbed above 220 and the oil is like it should be, translucent black vs. milkshake previously. I'm using drum band heaters at work but you can bet I'll be setting up a boiling tank at home with a cheap hot water heater element. I plan to boil the oil then put it in my storage tank. Only when it obviously has emulsified water of course.
I really like the upflow for really dirty oil or oil with free water/antifreeze. I'm moving it in front of my storage tank in my process. The process will be as follows:
Pump into garage
Boil if needed (then cool)
Upflow into storage tank.
Pump from storage tank to mix drum prefilled with RUG.
Mix and let settle at least over night.
Recirc 2-3 hours through my filters
Pump through the final filters into my finish storage tank or into my truck.
To do this I've built a 55 gallon drum funnel for the upflow. Just a closed head drum with a hole to put my pump hose in to fill it.