OK, thank you for your feedbacks. So, if I understand well, the main problem is the fact that convection with the Lotus requires much more heat than conduction with the vapcap. For sure, the candle can burn the herb in the latter, but I don't know if it can get the Lotus red. The vapcap is also supposed to be used with a torch lighter, but it works as well on a candle, it just takes more time to heat.
I am familiar enough with the quality of combustion and how to avoid incomplete one, but that's indeed important to mention for people not caring about that. With a vapcap, I do not need to keep it on the flame to inhale, not even when heating it in fact since the heat flux is far enough 1-2cm above the tip of the flame. The Lotus is wider, so I see how the flame of a regular candle could be easily hindered. Perhaps the steady flame of a good alcohol lamp with the Lotus at 3cm for a few minutes would work as well. I don't know whether the heat can settle enough in the wood to burn it in this slower heating regime.
About gravity, do you think an additional screen is mandatory to retain small vegetal dusts? In think I have a thin one. Thanks for the tip about the keck clip. About the magnet, please just give me a confirmation, I could only find a quick mention in a video.
About the linked glassware, I cannot see this offer from my region apparently, how is it called?