Ok but why not throw in some 20W50 and why do Mazda say 30 grade?
Put your favourite oil name plus pdf in the search line of Google and it will bring up the data sheet. I put a few popular oils in a table in order of thickness and it may explain why the guys with 90psi oil at cold have that excess pressure; the oil is thicker when cold than the bypass (60psi) can handle. It won’t be a problem warmed up but I would go easy til then as it must put extra load on the pump and gears and will not flow round the engine so well.
These are the industry comparison temps; 40C is hand warm and 100C is boiling water around fully warmed up, though track cars will run the oil hotter still. It’s a controlled running environment, ambient temp only comes into it when the engine is cold. We can see that even the thinnest oils are massively thicker at lower temp than the thickest ones are when hot, and at their W temp they are of course thicker still. It’s also interesting to see how the “fuel saving” 913C grades are still 30 weight but are chosen from the lower end of the viscosity spec.