The more pulls you do the more time you need... I forget the compound now, but a friend recently pointed out that we could get out even more, why do I think it was ether? Anyway, it was one of those chems that make you feel like a creep when you buy it.
If you break through to another world is dosage/person dependant, shoot too high, and you'll just have a confusing jumble of colours and then come out of it, some people are just more prone to haveing entity contact than others. I think its about 40% of people. A good point for those experiences are around 60mg vaped... I would in fact suggest you first get used to sub beakthrough level to see that there is no mindfuck, it is visual and "gnostic", you just have to get used to yourself, in fact its a little like one's mind alters a little when you swim underwater.