If you read that blog you would find that the methodology used is very basically to rub two pieces of metal together while pouring oils tested between them and applying pressure until the metal breaks through the oil film, scoring the metal. The Rotella 15w40 is rated at #222 (at 72,022 psi) of the 279 oils tested. Maybe take a look at #71. 10W40 Valvoline MaxLife High Mileage synthetic blend (red bottle) = 103,840 psi. With that you would get the 40w for hot running and a 10w for better oiling at cold starts. Also the extra advantage of seal swelling additives to reduce oil leakage. Personally I would go with #16. 0W40 Mobil 1 “FS” European Car Formula, synthetic = 127,221 psi. You would have much better wear resistance @ 127,221psi with the 40w you need for hot running and 0w for good flow to bearings on cold starting. I am now running #1 on the list 5W30 Quaker State “Full Synthetic” in the green bottle, @152,674 psi. I use to run the Mobil one and recently changed to QS 5w30. Oil pressure drop when going from the 0w40 mobil one, to 5w30 QS was 2-3psi at a hot run, and raise of 5psi at hot idle. Oil pressure now is 42-45psi hot highway speeds and 25-35psi at a hot idle. The QS 5w30 can be had for about $23 per 5qt pail at Walmart, a pretty reasonable price. You can also raise the oil pressure by dropping the pan and installing a high capacity oil pump.....a lot of work with only maybe getting higher oil pressure you are looking for.

Just my relatively informed, off the cuff, back yard mechanic, gut level, eyeball it up and guestimate, (based on some actual research) opinion...that's all...