Leaking issues in my 200 4R - any gurus available?

You'll want the sensor in the pan. That way you'll know what temp the oil is being picked up through the filter. Some will argue this though. If you had a cast pan, you could drill and tap right into the pan and screw in your temp sensor. That's what I have done now in the 727 pan and plan on doing the same when I swap to the 200-4R.

I'm surprised it's still getting hot though after the cooler swap. I never see temps over 180 in mine with a 5500 stall converter and cooler. Full throttle pulls, stop and go traffic, doesn't matter. I don't run the cooler lines through the radiator either. IMO the radiator is going to keep the oil hotter if the engine is always operating above 200 degrees.