[VAC] rivet selection

["Joseph J. DeLillo" <tooljd@xxxxxxxx>]

I'm on my search for the perfect rivets for my Airstream. My questions
are; what are the correct sizes for my trailer. I have a 59 overlander
that I'm in the process of restoring and it's essential that I use the
right ones. I know the type (Olympic Style) already. Question;do I need
to utilize back up washers on the panels? Or on the belly pan sections?
I don't think all the rivets used are 5/32''. Maybe I'm wrong.
  Any help will be appreciated.
 Also, do I need to use Vulkem on all these rivets that I replace? How
did they do it at the factory?
                                      Just trying to do it right,
                                       Joe DeLillo
                                       59 Overlander
                                       tooljd@snet.net