Just get one set of efficient speakers that can adequately fill your space with the sound you want at any volume level. I don't understand why any bar owner would want an overly complicated sound system for a small venue like that. The right music is the key in a bar atmosphere, not all the pretty lights of a vintage system. If it were mine, the system wouldn't even be displayed, especially behind a busy bar where it can be easily damaged. It would be as simple as possible. The overall sound quality will never be optimized in that space unless you plan on spending a lot of money on acoustical treatments. As I said before, vinyl would be a no-no. How many times do you want to hear your patrons yelling to change the album every 20 minutes or so and your bartenders are busy? How many qualified people will you have that will properly handle and clean your vinyl, and operate the system? Hiring a full time DJ will negatively affect your bottom line. Keep the system simple, offer a variety of music genres that appeal to the majority of the bar's patrons, and be able to cue up requested tracks or entire playlists with a few clicks on a laptop or tablet. Have a night or two with a live acoustical performance by a local talent. That would reinforce your place's reputation as an intimate music-oriented establishment.