Get some mullein, it's cheap.
Let's say you have a gram of DMT
250mg mullein, 250mg freebased harmala, 250mg caapi leaf, 250mg spearmint
add ground herbs and harmala to small jar, add enough solvent to cover them (iso or acetone) and then add your dmt at a 1:1 ratio. Stir periodically while evaporating. I wouldn't use the darco personally as its very woody and doesn't really absorb spice.
After drying, you can even sprinkle more dmt on top of your changa to give it a nice frosted look, higher potency, and delicious neurotryptamine taste.