I finally got around to making a new penny stove a couple days ago, and made a new pot stand for it (still working on the stand a bit). On my old one the simmer ring wouldn't quite fit down into the top of the stove because it was slightly bent and the burner was set too deep into the stove along with some other minor things.
On my previous stove I used three 1/16 holes under the penny, and rarely had any center flame at all. On this one I went with 4 holes (the bit I had this time was actually a few thousandths bigger than that, but basically 1/16) under the penny. I had tried a slightly smaller hole size but it over pressured and popped the penny up a few times somewhat violently so I opened them up a bit. This layout gives a center flame for quite a bit of the burn time but no "pops".
On this stove I decided to try the fiberglass insulation inside the stove. On one lighting, the fiberglass slightly plugged up one hole, and i had to split a small splinter off a piece of wood and push it back down in out of the way. Tonight I decided to test the theory that with the insulation in, if the stove got dumped over sideways no fuel would spill out. As you can see from the pictures that follow it does not spit out any fuel when on its side. The fiberglass also seems to make it prime faster, but I dont have any exact numbers to compare with. It definatly didn't hurt any though.
For the stand, I went with half inch hardware cloth because my pots are a bit small for the double u wire type stand (the one usually shown with the penny stove) to work well. At this point, I have the ends of one side of the stand hooked back so it can grip anywhere on the remaining wire to make the stand smaller or larger. That also allows it to be rolled up tight against the can when packing it. I may end up going with a fixed size for it though, I haven't fully decided on that yet. If anyone is interested I can post some better pictures of the stand, but I think it is pretty straight forward.
with original simmer ring
this is with the Bill Waite simmer ring I still cant quite get it to fit well for me. I'm thinking maybe I need to smooth/level off the bottom of the ring a little more.
and last but not least, the "spilled" stove pics