I know what your asking, but dont know of any info or research to answer your question, but I can tell you this, about 5 years ago I dissected a Federal 168g GM Match round, and it had 44.0g of Varget in it, and if its good enough for Federal and Hodgdon, its good enough for me. I use more Varget than all other powders put together, and I'm not worried about it.
All modern smokeless powder are a Nitrocellulose based powder, to my knowledge, so I dont know why one would burn hotter than another. But not to be confused with burning faster, and faster means hotter, most likely, but Varget is in the middle of the burn speed pack.
I do know the Navy did some studies in this area around WW-2, but they were talking about large naval guns.
The next time you see the guy that told you that, ask him where he gets his info.