Invitations are sent to each sanctioning body inviting the top 5 from each "association" - if top 5 can't come it gets handed down.
Rules are merged...ie. no garnish, BIG boxes, select 3 of 5 meats (whole hog, pork, ribs, chicken, or brisket)...blind judging (very much KCBS and FBA style), etc.
Nice prize pot, nice awards, great weekend...especially if you cook the Invitational and the Open like we did (Southern Brethren) when we assisted Nancee and Greg (Purple Turtle Catering).
Oh yeah, you can use wood, charcoal, electric, gas, etc. -- you just have to declare what you are using. Lots of homemade rigs, local churches and civic groups, etc. Also a "show" with many cooker manufactureres...Ole Hickory, Southern Pride, Lang, Tucker, etc. etc. etc.