I just got the Kindle DX, and I had the Kindle 3 setup on Calibre. On the preferences I believe I set it up for Kindle 3. Now when I transferred my library to the DX I did change it to the DX.
The question is I will be transferring to both Kindles, do I have to change it, or does Calibre know this is a DX and this is a Kindle 3 and does it even matter?
Very helpful thread I had the same question