First things first, try around 100mg DXM to see if you the enzyme deficiency then wait an hour or so. If all is clear then imo take around 250mg and have cone of weed, that should put you on a nice 2nd plateau, don't go for third plateau on your first time. Remember the 1/3 rule, 1/3 hate it,1/3 don't care much after trying it, 1/3 love it.