"If you have a reasonably good illustration program like Illustrator or Photoshop."

???? These are reasonably good? LOL.

The real work here has to be done in your head.

The area you have is x by x, tables are x long and x wide.. opens space is x big. Get the picture in you mind and then find some way to draw it, lots of options there and it sounds like you are on the way. Graph paper, they still make it and it works. I do use design programs all day long, but often do rough layout on bar napkins. Might be you need to start at the pub.
Nick