CJC Offroad here in Long Beach, Ca is very experienced with late model Ram HDs and all other fullsized trucks. Here is a video for 37 fitment.
With what you ordered from Thuren, all you are really getting is a 1/2" leveling kit. It is technically a 2.5" kit for regular Ram 2500 trucks because the Power Wagon in stock form is a factory 2" lift. In the video, you should be more concerned as to what the backspacing is for the wheel. For example, the Method 315 is a 17x8.5 with a +25 offset which is a 5.80" of backspacing. No matter what, you will need to do some trimming and CJC Offroad has a video about that. I highly suggest reviewing the wheels you ordered and see what backspacing they are. It should be around 5.75".
Keep in mind that not all tire brands are the same and not all tires types will fit the same. For example, I have 37x12.5x17 Nitto Trail Grappler MTs on stock lift. I rub when I flex and sometimes I rub when fully locked either way in steering. If I had Nitto Ridge Grapplers or Recon Grapplers, or BFGs or Toyo MTs, I wouldn't rub unless fully flexed out.