I'm not an expert in BWS, but perhaps I can help provide a conceptual framework.
People tend to overestimate the size of smoker they need. You can get a lot done in a cabinet the size of a Competitor.
C'mon! It's a business for heaven's sake, you know what your daily and weekly volumes are to the nearest pound. Since you give no indication as to what they are, how can you expect a meaningful recommendation?
I'm by no means an expert in BW Smokers, but the problem with nearly all cabinets is air flow. Figure out your needs based on volume, figure on the next size up so you won't have to fight bad flow, and you'll still be hopelessly confused. Call Mike, tell him what and how much you want to cook, how often you're going to be cooking it, and ASK.
If you, or someone else, will regularly and reliably check on the pit during every cook, you don't need auto-water. If there's a chance it will be overlooked, you do need it.
You do want a Guru or Stoker. They're relatively inexpensive ways of ensuring (up to a point, anyway) consistency. Consistency is a big piece of the commercial puzzle.
There's mobility and then there's mobility. If you're going to be schlepping the thing on and off a trailer every snow-free weekend, that's a lot different from planning on moving to a new space in eighteen months. If you don't know what you're going to be doing, neither does anyone else. On the other hand, mobility is mostly big casters and tie downs. Not particularly expensive, so why not?
I've heard good things about your restaurant (from where or whom I can't remember). Way to go.