ok. just for refferance here.. on a standard rb26 no oil restrictors and stock turbos ie: not much power
i installed a mechanical oil pressure guage and on a straight flat road, with the oil level on the high mark,
from a standing start (fast take off but not a launch) the oil pressure was surging the whole way thru first gear and partly in second..... and this was a 220-240rwkw gtr.
it took an extral 800ml to stop it surging in first gear...
so if you have good power without any sump mods. (tomie bafle does nothing on acceleration) you will have been surging. so if this is so, your engine would of been ingesting foamed up oil.... not no oil, but badly airated oil.
and yes. seeing it all is the only way to tell.
but if the bearings are all the same, im guessing its an assembly/start up fault.
if the bearings are worst on 1 and 6 bad on 2 and 5 and ok on 3 and 4 (see the pattern) its oil starvation.
if its the opposite or just one or 2 like that with the nearest main bearing also dammaged its dirt..
my guess anyway. need to see all the bits..