I definitely agree with the previous posters regarding "help". To maximize your sales/profits you should have more than one helper. For those numbers I would want at the very least three (3) other people assisting.
We do an annual one day festival that pulls 3K-4K in attendance. There are numerous food vendors and we end up with about 300 sales all in a 1.5 hour time span. We have 5 people working the booth and it is CRAZY fast paced. If we didn't have that amount of staff we would not be able to server those numbers and would probably lose half of those sales to other vendors.
I would also suggest cutting down your selection. Keep it simple. Also beware that ribs are a tough item to cook/serve at a vending type setup. Our vending menu consists of Pulled Pork/Pulled Brisket sammies, choice of sides (cream corn, smoked baked beans, coleslaw), potato chips and beverage (bottled water, canned soda). We sell the items individually and let the customers decide on what product mix they want to order. We keep all prices at even dollar amounts so we don't have to use coins for change (sales tax is included in our prices, makes the sales easier). We tried ribs one time and found that it takes too much time to cook/serve them and the price was not well accepted by the customers. (this will vary depending on the attendees and the type of venue you are at)
Pricing for our vending goes as such.
Sammie (6oz meat on a 3.5" bun) = $7 (our cost ~$2)
Sides (approx 4 oz) = $1 (our cost ~$0.30)
Beverage (12 oz water or can soda) = $1 (our cost ~$0.25)
(of course pricing is a regional thing so take that into consideration as well)
Do I smell SMOKE?????