I'm a commercial operation in Oregon. You will absolutely want a quality chamber vacuum sealer from day 1. We bought our first one the first year we opened up the doors and are up to 3 of them now and all have more then paid for themselves. The little home 'food saver' models are crap and will most likely not be allowed for commercial use anyway by your state inspector, let alone the federal inspector. Unless it's made for commercial use, you're flirting with disaster.
For local sales I'd still recommend vacuum sealing your products. It's more convenient for the customer and makes display a lot easier on your part. If you're doing strictly dried, that may be another thing, but I vacuum seal all my cured & smoked items for sale in the home store as well as for taking to the farmer's market.
Bag sizes are an easy one- look for a local distributor and they can get any size you want. Look up meat products, meat processing products, supply, paper supplies, anything of that sort. I have 2 companies I buy vac pouches from, one is my spice guy the other is my paper supplier. I have a number of sizes I use, from 2.5x8 (2 snack sticks) to 40x30 (whole hams).
If you're shipping, then yes, you will want it vacuum sealed. God only knows what it may come in contact with and pick up off flavors from, so sealing is a must, not to mention the sheer cleanliness and convenience for your customers.
Something to bear in mind is inspectors. If you ship strictly inside TX, you only need a state inspection and federal inspection periodically, depending on your state laws. If you ship over the state line, get ready for a whole ream of regulation. At that point you have to be certified as (or use a) USDA inspected facility, and all intake, production, packaging and storage have to be done under a federal inspector's eyes. I could make a boatload more money then I do, but the red tape involved with internet shipping is not worth it for me.