Have been experimenting with this over the last couple of weekends and have yet to have any negative experiences (apart from the shits).
I have been upping the dosage slowly over the weekends to get the feel for the chemical, max single dosage about 35mg and probably about 50mg over 24hr period.
Have to say it feels like one of the most controllable drugs I have encountered (at these doses) , I know this might sound strange but you know you are fecked, yet you can have perfectly sane and rational conversations without anyone noticing!
For example I was at a party last week lying on the carpet stretching and laughing at how fucked I was (with another person on aMT) staring at lights and shadows....yet head space was ultra clear, 2 minutes later walked into crowd of drunk people and acted normal....hard to describe but it feels like you control the drug and not the other way around.
When on it I find myself thinking no one would struggle with this substance at lower dosages, however that's not to say I might take 5mg more and freak out!
As always slowly find the dosage that suits you.
Also for me I haven't suffered from any discomfort at threshold dosages (I have read about people not liking the stimulation) so even low doses have been pleasant for me!