Ok, so after getting my running issues cleared out (turns out I had some dirt in an injector...) I finished with the install of the brakes and oil pump from a low oil pressure issue. So after the oil pump install I still have low oil pressure, not enough to trigger the light yet, but it's just below two bar at 2k rpms and at about 3k rpms I think I hear an engine knock of sorts

At idle after the oil is at temp it will be as low as 10PSI in the head. So at this point I'm looking at putting in main bearings to try and slove this.
My question is, can you do these in the car by "walking" them in? I had heard of this working on a regular gas VW 4cyl but not on a diesel.
Also, do I get stock bearings? or the next oversize? Is this going to be a temp fix and I should be looking for a shortblock?
Oh might help to know the car.... :p it's an '86 Turbo diesel Jetta with 208k on it.
Thanks a bunch guys!