Step 4: Cut the top
I cut off as much as I needed, put it in the parking lot, and ran it over with my bus a few times to flatten it out, and then finished it off with a sledge hammer.
Put the stove on the plate and trace the circle, I would highly recommend borrowing a plasma cutter if you can find one to cut this out with, it was quite a niussance trying to cut a curve with an angle grinder, lots of corners.
Once you have your circle cut out , clean it up and weld it to the top of the stove, making sure your grate is in the bottom first.
Make a ring out of a 2" wide piece of scrap, just big enough for your stove pipe to fit into. Cut a corresponding hole in the top of the stove opposite the door, and weld the ring in place. If you don't have a holesaw the right size, just use the biggest one you've got, and grind out the difference. I didn't have any grinding wheels small enough to fit in the hole, so I sandwiched together a few of the cutoff wheel stubs leftover from cutting up the bottle, as you can see in the last picture.