Thanks for all your suggestions and thoughts.  I've noticed that some suggestions are made thinking that this is an out of control condition, it's not.  All I am wondering (and probably should have asked) was who has better dampening rate, Bilteins or Rancho's.  
After speaking with Firestone, they recommended the settings that I was using on the bags.  That's the luxury of the air bags, you can add or take away.  Especially when I get my compressor and gauge installed.  Just dial it in as needed.
As far as there being a problem with the truck or trailer.  No problems!  Just trying to tweak it in a little better!
Thanks again.