There are as many opinions as there are Skylines

There is a HUGE discussion on the Australian Skyline forum that goes into painful depth, but fails to reach a universally agreed conclusion. A search here will give a lot of opinion, too. Personally I think a return to the sump UNDER the oil level is totally wrong, I have done it quite differently. IMO half the problem is tired engines that produce a lot of piston blow by. I would use a head feed oil restrictor, for sure.