Centering the extent of a Data Driven Page

[KenLucas]

Please see the attached screen capture. How do I center the DDP index boxes on the buffer circle I created for a number of towns?  I've tried centering the buffer circles in a layout view extent before running the DDP Grid Index Feature tool and continue to end up with the index rectangles generated off center. I'd like my buffer circle to fit neatly within one index rectangle per town.
Ken

[ChristopherThompson]

Please see the attached screen capture. How do I center the DDP index boxes on the buffer circle I created for a number of towns?  I've tried centering the buffer circles in a layout view extent before running the DDP Grid Index Feature tool and continue to end up with the index rectangles generated off center. I'd like my buffer circle to fit neatly within one index rectangle per town.
Ken

Are you creating the index layer on the fly with a script? or doing this in advance?  If you're doing it in advance, then you can edit the index layer and shift it so that each 'square' is centered over a buffer.

Alternatively (this is possibly what I'd do instead actually) - use your buffer layer as the index that drives your map pages - that way each page will center on the buffer at what ever scale you want to use, or a % of margin area around each buffer.  Keep in mind, depending on what you do with the buffers in the map, you'll need set a copy of that up as your index layer that you can turn off in the TOC and which only serves to drive the mapbook pages.

[KenLucas]

Christopher,
  I gave the above centering challenge hours of trial & error yesterday and you offered two really effective ways to handle it that I'd not, remotely, considered. I never thought of simply editing the index layers to fit. Although simply specifying the buffer as the index layer, in the DDP wizard, is the most effective thing to do. I just tried it and I ended up with page driven buffer circles, which will work great for my project.  You really made my day with your advice.  Thank you so much for helping me.
Ken