LOL, been going long enough that I forgot the vid! Haha. Your link starts AFTER his whole spiel. He goes into detail exactly why negative up is a bad idea and then explains why that mod is ok to use like that (delrin lined).
The whole explanation is there, did you skip through the video? (I skip to the blow up sections all the time, so I'm legitimately asking).
I saw the whole video and I added the time argument in the link to describe more specific what I mean.
I found the video while considering purchase a Broadside. What I see is that the Broadside is "made for" positive down usage.
I have a GeekVape Karma and Tsunami mods and the tube construction on these looks some similar to the Broadside.
Lined inside the tube all the way up to the 510 connection, vent holes at the fire button, but haven't seen any reviews of those mods (Karma and Tsunami) with the battery facing positive down.
I'm a bit confused I must admit ...