Rad stalker here; I only use Contaminated Strike, Radioactive Smash, Assassin's Corruption (duh), and Atom Smasher. All them other attacks are junk. Devastating Blow is a good way to stand there and watch yourself die during a wind-up. Radiation Siphon was pretty unhelpful. Proton Sweep is so meh I used it twice and took it off my tray while leveling. AC->RS->CS->(RS->)AS rinse repeat on single, aoe is cycling between Atom Smasher and Cross Punch (with Ion Judgement sprinkled in). I use the Guile proc on AC to go back into Hidden for RS crits, and most of my AS are special crits.
It helps I have permahasten though because Rad is miserably slow otherwise.