From looking at the pictures did you ever verify the bearing gap to the crank with plastigage? If it is too tight then any little bits of debris will score the bearings. I dont see any copper so they are not too badly worn. The front #1 bearing is always the worse for wear in general and sometimes when you first start the car it will rattle a little bit and then stop. If it was too loose of a fit you would have bad oil pressure.....you had 15lbs at 800-1000 rpms when you should have had 20-22lbs so that would have been a sign to me that there is an oiling issue. Sometimes it pays to have someone else do the bearings; crank, rods & piston assembly work for you.