It just fit on its own. I used 3" aluminum vent and bent it to contour the lid. It barely touched the warming rack in a small spot. I take out the rack if I do lots of ribs in upright racks, but like to use it for the more delicate foods like shrimp or ABT's. I've got some other good mods to share once I finish them all and take some pics. I fab'd a charcoal basket by bending some expanded metal and welding angle to fit the grate holders in the smoke box. It worked great Monday. I also am working on a baffle out of some heavy guage sheet. You can see it in some of the Q-View. I'll put out more details after I finish it.