I don't know what to tell you about the vine extract cause I'm bad with math, other than you'd be looking for 250mg harmalas. I would start out with 50mg DMT, but if you're looking for a really strong experience, then maybe you should start with 75-100mg. The most efficient and effective way I find for controlling how deep I go and for how long is that I take 50mg DMT and then once it's kicked in and I start seeing patterns, I then load up the GVG with 20mg and take a hit or two and that'll blast me into unparalleled dimensions for about an hour or so until I'm back at whatever I would be at had I not taken the hits, but then if you've decided you've had enough, you can simply put the pipe down and let the rest of the trip naturally unfold, or if you decide you could go back for more, just take another hit or two to be up in the stratosphere for another hour.
"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