I havent done it,(wish Ihad) but POR15 seems like the way to go. They have
a product called porpatch.  www.por15.com. Gouge the old out, and  squeeze
in the new. Make it pretty with your finger.Prep with por15 marine clean
and metal ready. Go nutz and do em all. The only down side I see, is if you
have had previous body damage. Sometimes this is around seams, and it seems
that the sanding can change the body shape,making it obvious that damage
has occured. Need to be careful. Problem is that you will find this out as
you gouge your seams. By then,you are commited to finishing the job.