I knew someone would ask me this, and I'd have trouble explaining it, but here goes.

There were no relief cuts made, the material of the sidewall of the can is thin enough that it can be easily formed without reliefs, and seemed to be pretty malleable.

When I lopped the top off of the can, I saved the top rim down to the widest point (man this is tough to explain). Think of it as the shoulder of the can. This part is thicker, and very sturdy, and could be inverted, and pressed down into the lower portion. I basically pressed this part down into the lower portion until they were flush with one another, and then pressed the top rim portion in another 1/16" or so. This left the thin sidewall exposed and unsupported, and it could be formed down with just a fingernail.

Once the first 1/16" was folded over 180 degrees back onto itself, each consecutive fold could be made with a pair of pliers, gradually working your way around the rim. The first two folds were rolled a full 180 degrees on itself, and the third (last) fold was rolled 90 degrees, so it sticks out as much as possible to support itself on the cone.

I wish I had some pics of this, because I realize that explanation is really not very good. A video or at least some stills would really help I'm sure...I'll see what I can do.

As for the cone, the video I used as a basis for my design can be found here: http://www.youtube.com/watch?v=VerP7-aiEBw

The base is 5" diameter, and if I remember right, the top diameter is approximately 3.25". The height I don't recall, but I was shooting for the bottom of the pot being 2" above the ground, something like a 1.375" gap between the top of the stove and bottom of the pot.

The ventilation holes on the bottom were made with a paper punch, and span about 170 degrees around the base. I didn't want to put holes much further than that, thinking that wind could curl around the base and still get inside if they went 180 degrees around the base.

The vent holes on top circle the entire cone. I tried a cross-venting idea, where the holes were only placed on the same side as the entry holes on the bottom, but this failed miserably, and actually caused the fuel to boil off and condense on the pot. Putting holes fully encircling the top worked much better.