They can be taken together or separate as you've been doing. Everyone has their individual preference. I tend to do the half hour wait. I typically try and keep the brew down for an hour, and then I try and purge so that I can enjoy the rest of the experience nausea-free. If I can't get everything up (or anything at all) myself, at the 1-hour mark, I typically like to vape some DMT. If there's anything left to purge, this usually sends my ability to keep anything down through the floor. Now of course the drawback is that if it happens to you like this and you're anything like me, then you'll be purging while having some of the most intense hallucinations of your life. Following that purge, I'm usually devoid of physical energy, but luckily nausea too. It's not too much of a problem that there's no more physical energy at this point because I'm usually ready to just lay back, leave my body on the couch, and go off exploring some of the deepest reaches of hyperspace that I tend not to have access to on other occasions.
"Science without religion is lame. Religion without science is blind" - Albert Einstein
"The Mighty One appears, the horizon shines. Atum appears on the smell of his censing, the Sunshine- god has risen in the sky, the Mansion of the pyramidion is in joy and all its inmates are assembled, a voice calls out within the shrine, shouting reverberates around the Netherworld." - Egyptian Book of the Dead
"Man fears time, but time fears the Pyramids" - 9th century Arab proverb