Related thread on proper 300TDi filtration/sedimentation, started recently by yrs. truly: http://www.defendersource.com/forum/...tor-64050.html
I had a setup similar to the one you're currently running, except it really was a gasoline filter, and . . . the lift pump had been connected by mistake to the return line, so my fuel was running backwards through the wrong filter on its way back to the tank . . . suboptimal.
I used one of Mr. Davis' sedimenters and am quite pleased with the result.