I'm a very fast metabolizer as well and very skinny. I've always used 3g rue, no more no less. Always works like a charm. I also wait half an hour in between. I like to put the rue in gel caps so you can't taste em. I then poke holes in them before ingestion with a thumb tack. I use the "0" size, can't find the "00" near me. With the "0" 3g ground up seeds fit into roughly 13 capsules. I'm pretty good at swallowing pills so it's not really an issue. Personally I never "feel" the rue at 1/2 an hour in except as you put, maybe a little bit of gas
My suggestion, take the 3g rue, wait 1/2 hour then drink the DMT-concoction. I might also hold off on the apple for a little while until after you've consumed the DMT cause I find that eating something small is more effective after you've allowed some DMT to already be digested than to block up the initial digestion with an apple.
"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