> I don't really get the latch by looking at the picture.
Imagine a simple, cylindrical windscreen, made from a rectangle of foil.
At one end (end 1), cut a slot at the top, close to the end, and cut a tab at the bottom, at the same position (using two V-cuts, one at each end of the tab). Fold the tab towards the 'inside' of the screen.
At the other end (end 2), cut a slot at the bottom, close to the end, and cut a tab at the top, at the same position (using two V-cuts, one at each end of the tab). Fold the tab towards the 'outside' of the screen.
Now overlap the ends of the screen, so that end 1 is outside and above end 2, and slots and tabs are aligned. Slide the ends together, removing the vertical soffset, and mating each tab with the slot in the opposite end. Lifting the tips of the tabs a little helps the joints slide easily into each other. I can do this with one hand (when showing off...) Having the upper tab outside the screen means that it's protected from the flame, which might otherwise melt or soften aluminium foils.
> Your joint looks a little more sturdy but it kinda has to be to hold up the pot.
Yes; in a cone, the joint must stop the cone unwrapping when the pan is placed in it (although the rolled lip of the pan also helps a lot here).
> The thing I don't like is the pack real estate the cone uses.
The two-part, horizontally-split, Flissure variant usually allows the cone to fit entirely inside your cookpot*, so it takes up no additional room inside your pack.
* depending on the form factor of the pot; shallow, wide pans may not allow this.