Thanks for the help John;
Is your rad cap correct and new? (0.9 bar, typically)
It is OEM, .9 bar, unknown age.
Is coolant purging from the system?
Coolant is not purging.
Were you getting warm air from the heater vents with the heater on?
Lukewarm at idle, hot at higher rpm>>900
Does your fan have resistance when it's warm, hot, cold?
Stiffest when hot, looser when warm, loosest when very hot; still moves air though.
Are your belts properly tightened?
Belts not loose, not super tight either.
Is the fan shroud in place?
Fan shroud installed.
Is your rad plugged internally or externally?
I don't think the rad is plugged anywhere; both air and coolant flow freely. Fins are in good shape, and it flowed exceptionally well after the acid flush.
Do you have the correct type of thermostat installed?
Thermostat is a "motorad" 185 degree all brass unit. Opens at temp.
Are you sure it's actually overheating? (don't trust the factory gauge)
Readings were taken off an aftermarket electric unit with degree units installed in the factory sensor port in the head.
When does it overheat? (highway, around town, idling in your drive)
It used to only overheat on the off ramp after driving at least an hour at ~75mph. Lately it has escalated to reaching 212* after idling for 7-10 minutes in ~50* weather.
How long does it take to get to that temperature? (how long and at what speeds)
In the highway off ramp situation, less than 2 minutes. Very quick. I would exit the highway, be hot, let it idle at the pump. Refill time of about 2 minutes, and leave the station. In less than a half mile, the temp would be back down 200*, as if rpm helped circulate the coolant or airflow was needed.