So, which way did factory route the oil source line from reservoir to pump?  was it turned immediately from oil reservoir .. horizontal to frame, then down to pump?  or was it down, then horizontal at frame near engine, which sort of makes a J Trap effect. 

Does pump suck oil or just accept it gravity feed?  guess I could test it. rather not on new engine.  Thinking 50:1 mix in tank (small amount haha have a weed eater mix ready to go), initially to use oil pump also).  Once I see pump working correctly (measurement), can dump fuel in tank and back to pure fuel.
will be testing pump with drill first.

Thanks.  Close to cranking a rebuilt engine and don't want any fails!!
 

page 20 of service manual "appears" to have a pic of it descending down at engine side of tank...

Page 199 of service manual has a very clear drawing of the correct routing.

I've had to photograph rather than scan, but here are images of the cable and wiring routing diagrams from my original DT250A/DT360A Service Manual (Euro version). The route of the oil pipe is shown here.