I'm leaning towards binding Invasion as a separate book and I really don't want a 4 volume Captain Atom run (Invasion books are 80-pages each and I don't believe they have much for double-sided ads). If you wanted/needed to include the key Invasion storypoints, from his perspective, you could include the following:

Captain Atom 23
Invasion 1
Captain Atom 24
Superman 26
Adventures of Superman 449
Invasion 2
Wonder Woman 26
Captain Atom 25
Invasion 3
Captain Atom 26