The most important factor in the traditional way is fermentation.
The plant is nicknamed "sun-opener" by Indians, and sun plays decisive role in its preparation.
After simmering in water the brew shall be left for a couple of days in the bright sun. This part is usually omitted by most Western recreational users.
In Russian sector of the Net there are lots of reports on soaking in strong alcohol, usually vodka. Have never tried it this way but the reports state it's stronger and almost always works.
Waiting for some Sinicuichi 25x to come this week, will give it a try and report later.