i always get the most 'psychedelic' highs when i mix two types of haze or other high grade shit. Never full blown hallucinations but stuff like objects slightly growing, 2dimensional trees, bright colors, slight trails and tracers and CEV's ect... They seem to come out with when i smoke a blunt of mixxed weeds. So, my answer to you is for the most psychedelic like high mix your herbs.

Another thing is that once you consume a psychedelic drug other than weed, it seems to increase the potential of the grass tenfold. That may just be wishful thinking, but it seems that weed always fucks me up alot more after a real trip.