I haven't use eastwood products before, but I have used POR15 extensively. It's amazing stuff. If you have holes in non structural areas you can even use it to patch them. You coat fiberglass cloth with it and then lay it over the hole (having already treated the area with por15) and it will harden into a permanent patch that won't let rust grow underneath it.

That being said, if you can easily replace the panels with good ones, that is a much better option.

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2004 F150 4.6L -My Daily
2007 Volvo XC70 -Wife's Daily
1998 Ford F150 -Rear ended
1989 J-spec 420SEL -passed onto its new keeper
1982 BMW 733i -fixed and traded for the 420SEL
2003 Volvo V70 5 Speed -scrapped
1997 E290 Turbo Diesel Wagon -traded for above
1992 BMW 525i -traded in
1990 Silver 300TE -hated the M103
1985 Grey 380SE Diesel Conversion, 2.47 rear end, ABS -Sold, really should have kept this one
1979 Silver 300D "The Silver Slug" -Sold