I recommend that you try Duokan. With "manual trim" and "smart layout" you can view pdf's on Kindle much better than with the default OS. It is very easy to install, and doesn't affect the Kindle OS.
http://flip.netzbeben.de/2010/11/duo...ish-gui-today/
https://www.mobileread.com/forums/sho...d.php?t=105316
I don't bother coverting pdf's now, I just load them on my Kindle and use Duokan to view them.