I am uncertain if cone windscreens improve effeciency to tell the truth. The jury is out with me. If they do, my theory is that it is due to the distance between windscreen and stove at ground level creating a more 'turbulence-free zone'.
The main problem with cones is they are challenge to pack.
A pyramid would serve the same purpose but can be stored flat. Here's the basic math:

An automatic calculator can be found here.
This would be one of four panels.
The easiest method is to simply make four panels sized to your pot and tape them together to use as a pattern:

Trace them onto an oven liner and cut out the outline:

Fold it into a square and you have your basic windscreen. I left a tab on one end in order to make the closure "magnetic":


Here's an example of a Pyramid for a Heineken pot. This one weighs 1/2 ounce:

When not in use, the windscreen folds flat for easy storage:

Yes, yes, this one still requires a potstand. The obvious next step is to have a go at constructing one of aluminum flashing or other material that will also support the pot. My time is limited at present but I wanted to throw the idea out there in case someone would like to play with it.
