I didn't notice much difference between friends that smoked and people that didn't when it came to how long they'd stay off in hyperspace. I wish I could stay there for more than 15-20 minutes and I'm a heavy smoker. I think you may just be one of the lucky ones that can keep in that mind state for longer than usual or perhaps something else in your diet contributes to your ability to remain there for so long.
Probably something to this as well although I've never had anyone comment on DMT being too harsh. Compared to dirt weed it's very smooth. Also sometimes smokers have a harder time taking big rips off bongs. I personally have a hard time dabbing because wax just seems so harsh on my lungs. It's easy to get down but it feels like it gets deep down into all the nooks and crannies of my lungs and causes an awful burning sensation. I cough more from wax than any other substance I've smoked and this has been enough to keep me away from it most of the time. I only smoke it now if someone offers me a hit off of theirs and even then I take way less than most people.