Try taking the valve cover off and removing the rocker rod an bring the #4 or #8 all the way up. remove the valve spring and check the guide seal hole, from the top it should be a perfect circle and have no deformations. then try a wiggle test on the valves themselves and see what you come up with. I believe that therein lies your oil consumption.
It may not effect anything but if you do take the motor apart again check the alignment of the oil rings on those two rear pistons.
Hope that helps a little but checking the valves should lead to an answer of some form.
Scoring disabled. You must be logged in to score posts.