I've been following this thread on painting a Westy roof, primarily
because I've been looking at getting the same job done.  I may have
missed it, but there seems to be little discussion of the color involved
except for one comment that implies that you should be matching the
color of the van.  With the exception of the white vans, WRONG!  I spent
six years with an '85 with a white top, now I drive a '90 that was
originally dark blue, PO painted a dark blue/gray metallic.  That
includes the top, originally the same dark blue as the body. I think VW
changed about '87 or '88 to matching the body and top.  I'm planning on
having the top painted white or silver.  The difference in the amount of
heat buildup between the white top and the dark top is really, really
significant when camped in the summer, and it tends to hold the heat at
night.  I realize this applies to the whole body, but believe me, any
little bit helps.  So if you are painting the top, go as light as you
can.
BTW, the local paint/body shop has been trying to discourage me from
going with a silver paint on the top, says it won't hold up well and
does not reflect the sun as well as white.  For appearance reasons I'd
prefer the silver.  Does anyone have any experience along this line?
What is the silver paint used on RV roofs? Any other suggestions?