>> what does this do to clearance?  Are the tank and plumbing protected from rocks and so on encountered on back roads?  I ask because I have considered this, but am leery of an unprotected installation. <<

   No change in clearance if you're adding a tank just to run the
barbie.  If you want to plumb the two tanks together like mine, you'll
have to pay attention to how you cross over.  It's dark outside, and
wet, too, but I'll crawl up underneath tomorrow and get back to you.

Geo/ATL
'89 westy