I have some spots on a quarter panel with a few pin holes due to rust. A typical holey section is about 3"x3". See the dark spots in this photo (or here... http://www.creative-machining.com/claylahatte/auto/1971cudaconv_java/#IMG_1634.jpg).

The areas have been blasted both sides and are clean. What would be the best way to repair these kinds of areas?

A simple fix might be to put something on the backside, like fiberglass, and skim the outside with body filler. Or, I could possibly weld these holes, but I would hate to make them bigger by burning metal, not the mention the possibility of distorting the panel shape.

What do you think?
Thanks.