I have an extra grate wedged into my char-griller kettle, I set a pizza stone on it and then a drip/waterpan on it. Then put the grate on top. I haven't figured out what to do for a deflector on the webers yet, a rotisserie ring or extension is the route I wanna go. So the deflector and pan can set on the stock grate, then use a grate or two in the extension.
Here is the char-griller. It has a pretty good air leak at the ash pan, so I just leave the bottom damper closed and control temp with the tip vent lol.