Typically weight distribution is more about getting weight back on the front axle more so than trying to avoid being overweight on the rear axle. From a handling standpoint you don't want to unload too much weight from the front, basically. But I would agree that 1200 lbs of tongue weight won't make enough difference on your front axle to matter with the Cummins sitting up there. Check out friction bars on etrailer. There are several options starting at about $30 with good reviews.
https://www.etrailer.com/Weight-Distribution/Pro-Series/83660.html?feed=npn&gclid=EAIaIQobChMI7aH8kuHD1wIVTrnACh1hlQDvEAQYASABEgLEMfD_BwE
