I just got back from the Advanced Pilot course and I asked about the delta between high and low CHT temps and was told that a big spread (mine is about 90F between hot and cold) isn't a big deal and the engine will run fine.  However, it is a baffling issue and thats how you can solve the issue if you want to keep the temps closer together.   Continental apparantly doesn't publish a minimum CHT temp (unlike Lycoming) but they suggested that they would want to keep them at 235F or higher.