Ok so it says in your catalog that your NS Heritage units minimum radius is 22, but in a video by ModelTrainStuff they say it's minimum radius is 18, is this true?
The best answer is to run your layout at several inches above the minimum radius - running at the extreme edge of the envelope with 6 axle power is like being down on your knees begging and praying to have constant problems come your way.
Stick with 22" minimum radius to be safe, mine have trouble with 18" radius.