Re: Funnel/vortex bowl foil question
Hole in the middle will not help. If your foil is sagging you need to double or even triple wrap. Make it tight, try to get the foil wrapped in such a way it won't come loose easily.
You need to keep the coals well away from the center ring so that the foil doesn't get weighed down and the draw becomes hard. Sit them partly on the outer ring of the bowl in order to take some of the weight off the foil.
I use 3 squares of holes which I sit my coals half on half off, then a few little holes (2 or 3) in between the big squares. Haven't had a bad smoke from my phunnel yet.
Hopefully that helps a bit!
Also, I'd imagine using a 'scalli' mod would make the foil issues non existent, as the hole can't be blocked by sagging coal. I haven't needed to do that yet though.