Jay Brown's book points to oil levels in pan during dyno runs at cruising speed as low as 2 qts (he started with 6)  without the  drip rails  that get the oil off the heads faster.
Those rails do not easily work with Pr Oil Pump end stands but I made it happen after reading (pg 232 -235) that grim info.
Keeping the oil rails brought the pan level to 3 qts at cruising rpms.

Just my 2 cents.