sheesh, I think the guys are right, there "itsnitro." If your engine temps were always at 200 degrees, or above, with oil temps of 210 to 240, then your 20-50 would probably be just fine. (-also, I notice your location is Florida,,,)
But in the real world, I think you would be A LOT BETTER OFF using 10-30. (which pretty much pumps and flows twice as easily as your 20-50 with each "cold start.") Besides that, all of the engine'* internal "clearances and tolerances" are designed to use 10-30 or 5-30.
According to a lot of folks "way smarter than me" the majority of engine wear occurs each time your start it. -particularly in the morning, after it has set all night, and the only thing left between the moving parts is what little bit of "oil film" is left, that didn't drain back down into the pan. With each engine start, it is very important for the oil to flow as quickly as possible.
Heck, I even know of some "very heavy duty" engines that have a special system which pressures up the oil system for several seconds before allowing the starter to crank the engine. (by the way, it greatly extends the life of those engines)