Bresch,
Happy to describe how I put it together. It actually worked out really well. The charcoal goes on the charcoal grate like it would when you use it normally. I'm thinking about putting toghther a charcoal basket or ring like the WSMs. But I digress. After the charcoal goes on (BTW, I use the minion method) I put the grill grate on as it would normally go on and then place the heat diffuser (pizza pan) and then the water pan on top.
Here's the cool part. With the WSM Pro-Q, which you can find on ebay at fairly decent prices, there are clips for holding up the rack that's included. Well if you turn the Pro-Q upside down, it fits nice and snug (almost too snug) just inside the Smokey Joe. Then, if you turn the clips over you can place the rack on top of those clips. By doing this the rack, which was previously the top rack but is now the bottom rack, fits just slightly over where my water pan sits.
Now for the 2nd rack. I bought some screws, with metal spacers and wingnuts; 3 sets. I then drilled holes near the top of the Pro-Q directly aligned with the clips that I described before. Then I bought a regular Weber 18" grate and it fit perfectly as you can see in my pics.
So its:
- Charcoal grate
- Charcoal
- Smokey Joe grate
- Diffuser (16" pizza pan)
- Water pan (12" cake pan)
Then place the Pro-Q on upside down and insert
- Bottom grate (came with the Pro-Q)
- Top grate (Weber 18")
... and you you're ready to go. Also note that with the Pro-Q upside down, the lid fits on top perfectly.
Hope this helps.