Running hot with E fans

Hey guys,
I initially had an aluminum rad with clutch fan and didn't have any temperature issues. About a year ago I ended up putting in a new radiator since I was installing A/C and threw in electric fans. Now the engine runs pretty warm and it takes a long time to cool back down. It gets up to about 220 where the fans kick on, then it takes about 15 minutes for the temp to drop to around 180. Sometimes if it's hot out (90F) the temp doesn't drop enough for the fans to shut off under normal driving conditions and they just stay on. The set up I have is:
Mildly built 302
T-5 trans
A/C
ACP copper/ brass rad maxcore 3 core (PN:FM-ER006 from cj pony parts)
Dual electric 12" fans 2800 CFM w/ shroud also from cj pony parts with matching controller
180 deg thermostat

I've messed around with sensor placement, sealed up all the gaps between the radiator and shroud, replaced the thermostat, and burped it a number of times. No indications of a blown head gasket. I've thought about getting a fan controller that is variable, but I'm concerned that the temp takes so long to come back down. My next thought is to replace the radiator with an aluminum one but I wanted to see if anyone had a better idea before I start throwing money at problems. Any input is appreciated.
Thanks