They're not on the same strength class as .44 frame Blackhawks, Redhawks, or Contenders, which is why data in loading manuals is serparated into two classes. They can be loaded to give more power that factory loads and so loaded are very effective on big game, according to Pearce who has taken a lot of game with his SA Colts and others in the same class. To the best of my recollection, the load levels you cite for your N frames fall within the range Pearce uses. The stronger guns can be loaded to about 30,000 psi, well over what's safe in .45 caliber N frames and so loaded, again according to Pearce, hit game harder than .44s due to the larger diameter of the bullets.
I suggested that the OP look up the articles himself so he's not operating by the seat of his pants and risking premature wear on his gun or worse. I'm not dissing N frames in any way, but like Popeye, they "am what they am, and that's all that they am". That "am" is pretty good, I think.
They are definitely not in the same strength class. I wouldn't feed an N-frame my 30,000 PSI pet loads for any duration. Keep in mind, even with the endurance package, the N-frame was designed around the .44 Special and somewhere around 15,000 PSI.
