Ours has 5.25 feet between the back bar and the main bar. Considering that cabinets run 25" (with countertop overhang) you'll need approximately 10 feet to the back of the second wall if I understand your question. For our use, the 5+ feet workspace has been a very comfortable behind-the-bar space.

Linked are photos including a schematic. Hope this is helpful.

Here is a link that might be useful: Basement

thanks for the reply. I like the pics of your basement - sweet. So from what I can see - you basically have another kitchen for your bar. I had thought about this also - like the cooktop to do burgers or something... did you vent that out?

We entertain frequently and eveyone wants to tend bar - the space has been very adequate unless trying to do heavy cooking at the same time. Yes, a full second kitchen. The cooktop is a downdraft unit and is vented outside. We have the interchangable drop-in units for a griddle, grill or 4-burners. We've grilled steaks / seafood, griddled bacon / pancakes, etc. Works out really nice for large gatherings. And, when I get ready to remodel the main kitchen, we will still have one.

If you scroll below the individual photos, I have added information for many. This may be useful. Good luck and enjoy the final result.