As long as you stay under $10,000 in sales, the FDA doesn't require nutritional information. The way to "hot pack" a sauce is basically the same as home canning: bring it to 165 degrees for a minimum of 30 minutes, transfer it into hot, sterilized containers, seal and submerge in boiling water for an additional 45 minutes to create a vaccuum seal.
That being said, the liability for bottling and distributing your own product without proper equipment, training or knowledge is pretty darn big. There's a million things that could go wrong and cooking up a few cases in your kitchen will hardly get you the market recognition you need.
A co-packer is definitely the way to go. They carry the insurance (and the liability if someone gets sick), the do all the labeling and for a small fee, you can even get a bar code on the label (Personally, I think that's a waste unless you're going to try to market it to larger retail chains, but that's just me.) Most of them employ food scientists to help you with scaling up your recipe and will often offer ingredient alternatives to lower your production costs.
Find one that will do a small commercial run (200 gallons or less) and start with that.
From what I've encountered, and depending on your ingredient list, a 160 gallon production run of a basic, ketchup-based BBQ sauce should run about $3,000.00.
Good luck!
