After I wasted a lot of material with bubbles and pipes I decided to make a machine. I used a 40ml-bootle for it.
Up to now, I've only reached some threshold effects. If I just heat the mesh with the dmt on it, hardly anything happens. So I have to inhale very lightly, in order to make some smoke appear. I always have the feeling that I'm losing much of the smoke that way, as it's impossible for me to leave it in the bottle, some of it is already in my mouth or lungs - and I have to exhale it if I want to deeply inhale the produced smoke (which isn't very much, even after ~45 seconds)
If I read the reports from others, it sounds like they just heat the mesh and start inhaling.
What am I doing wrong? Any help is appreciated.

What lighter are you using? Maybe a jet will help you vape it faster?

I used a candle. Would a better heat source really make such a big difference?

Almost certainly, a hotter heat source would mean quicker vaporisation, thus denser vapor and a shorter inhalation time, leaving more time to hold the hit(s), plus you wouldn't be inhaling carbon / soot from the candle. Even with the GVG a torch lighter is essential IMO - you can get the entire dose in one lungfull within 5-10 secs this way, which really adds to the ease of dosing and intensity of effects. All smoking methods take practise how ever...

Enhanced leaf and/or changa There will be no issues....fairly full proof.

Section 14.1 - DMT Nexian Handbook

Thank you for your answers, I will buy a better lighter and report back

You do realize that you must keep the bottle opening with the mesh in it, pointing straight down the whole time, and keep the flame a couple inches away from the mesh. I also find that it helps to make a small indentation in the middle of the mesh so that the dmt stays in the middle and doesn't run to the glass edge. Melt it into the mesh be heating the outside of the neck of the bottle, so that it runs down into the mesh and then let it sit for a minute... when ready, hold the bottle with the neck pointing straight down at the floor and then fire away. Happy trails