'the oil temp gauge runs just a tick past the middle to the higher side'...
What is that supposed to mean, do you think we have a 2012 Mustang
GT oil pressure gauge on our desk to compare with yours ?
A tick past the halfway mark means absolutely nothing to me or anyone else..
Alright, the minimum operating engine oil temperature is 210F, the optimum engine oil temperature is 220F, this means the engine should be placed under a load UNTIL the oil temp has reached at least 210F, the only time an internal combustion engine is not under a load is when it's idling in neutral or park. Oil does not provide proper lubricating properties until it reaches 210F, do not move or drive your Mustang GT until the oil reaches 210F..
Don't get me twisted, i'm not trying to insult you, i'm trying to save your engine and your money, acquire and install a mechanical oil temperature gauge and/or use a thermocouple and external gauge to synchronize your generic unmarked factory gauge with the 210F mark, let the engine warm until the oil has reached minimum operating temp and you will enjoy thousands of trouble free milees from your Mustang GT, you'd bee surprised to learn of how many engine bearing failures are caused by repeatedly placing a load on them before the oil has reached minimum temp...
It has little to do with viscosity or ability to flow but everything to do with the composition of the oil.