Its worth mentioning the oil you see when you remove a valve cover is 'static' oil. That means it's there all the time*. It puddles up once you first start the engine then it stays there, at least in volume. So it really doesn't reflect how well the oil drains back. The trick would be to install a clear valve cover and watch how much oil puddles up in addition to the static amount.
Then, the more oil that drains back through the lifter valley, the more oil that can get beaten into a froth by the rotating assembly. If an old boy were strictly interested in the best 1/4 mile pass, he'd limit the drainback to minimize windage, then keep on hand lots of extra rod and main bearings in case he ran out of oil. The point being...drainback is good but too much in the wrong places can be bad.
Someone should invent a system that uses a crank-driven pump to evacuate the engine of 'used' oil, then send it to a tank where it could be held until the oil pump is ready to suck it back out and redistribute it into the engine. The sump of the engine would contain only the bare minimum of oil. While it wouldn't be completely dry, we could refer to it as a 'dry sump' type of system to keep matters simple. If I weren't spending all of my time modeling Hunter Biden underpants for Japanese tourists, I'd sit down and invent such a system.
*Unless you drive on a 45 degree embankment or perhaps some other embankment of a different, yet still effective, degree.
