Hi Peter,
How are the Lion Energy batteries working out so far? I invested in a pair made available through my Airstream dealer. They took out two factory Interstate Lead Acid batteries and dropped the Lion Energy's in place.
Before choosing the upgrade I called and spoke to someone in tech support at Lion. They were helpful. For now I am sticking with the WFCO factory converter but like you I am considering an upgrade later. I am hoping the 3-stage factory converter will bulk charge to the the mid-80% range and then a Zamp portable solar kit with a built-in charge controller that has a setting for Lithium will get me up to 100% often enough. If not, I can swap the WFCO for a Progressive or Iota that have lithium settings.
Please let me know how it is going for you so far and I'll do the same after I pick up the new rig in two weeks.
Thanks,
Scott