About the seams... I was doing some work on mine and i found that it would
seem that
the wheel well seams and on the under side go bad long before it is noticed
on the outside.
I put the van on stands and removed the tires for a better view and found
even more rot. hope fully i got it all and rivited new metal in place using
fiberglass mixed gell then por-15 after curing.

My 2 cents

Jim Morgan 86GL 'breadbox"