It's all about the density of the vapours - make it a 'fog' !

But to assure you make it 'through', do the Rue !

Or any good dose of naturally derived MAOI.   (3.5 g Syrian Rue seed extract is very good, or a tea of 10 - 15 g B. Capii). Then just 25- 35 mg dmt smoked gives an assured "9-minute-breakthrough" you'll remember.

I forget most of what happened on the other-side, but MAOIs are the fix for that.

With a dry, all-glass bong 30 - 40 mg can be vaped in one toke but you must 1) pre-melt in a small bed-of-leaf-and-screens-and-steelwool, and let re-solidify(2) Then once it's melted into the leaf you can heat it hard to get the 'fog' going - don't go weak on the heat, it's better to get it a-flame for a second than worrying about burning it, and going too 'cold'. Then inhale slow - so slow that the vapours are as thick and white as cream, get it all in, hold it as log as possible .. turn out the lights, ... Grok!  .