Does anyone wish to offer some clues or suggestions about how to install
the bottom pan on a vanagon AT without leakage.
  Generally I have held to the belief that clean straight surfaces and a
new gasket should be enough and silicone, etc. should not be needed.  In
the case of my current project, however, I may have to conclude otherwise.
What works?

Larry A.
  too many vangagons, too little time