Anrchy, I don't know how much success that you will have eliminating the harshness from the vapor. Based on my experience with nicotine liquid, it doesn't really seem to matter what carrier or mix of them that you choose to use, they all have a certain harshness to them that is just part of their nature. I asked my friend who is an E-cig freak and he has been having the same issue trying to find a smooth mix for nicotine alone without much luck.
I remember that you said that you had a G-pen or ripoff one, right? If I were you I'd try mixing a highly saturated solution of 190° and the DMT and just using the dab tool or an eyedropper to drop it right on the heating element like they recommend for viscous or solid honey oils.
I'm very interested in your results so far, very informative. If you still don't have any luck eliminating the harshness, I'd suggest the something like the omicron vape which doesn't require any liquid and has given great results with vaping all sorts of alkaloids and other substances.
I definitely hope that you find a mix that works though, good luck!