Viktor is my favorite pilot of the pack, but I'm not sure how to make him work yet.
I tried Deadeye, Harpoon, Chips, Stealth, Scav Crane, ran him next to Dengar and Sunny. He did ok, he was kind of scary with the deadeye missile. He doled out two stress, lost his SD, sunny blew up and he Scav Craned it back and handed out one more stress before he died.
I think the core of any build for me with Viktor is Stealth and Scav Crane to get as much out of his ability as I can. After that I'm not sure yet. I think he needs some help on offense and defense because Kihraxz don't hold up long to focused fire.