Gigi rides the superpro's. The contact pro's have a lot of torsional and lateral flex. So much that I don't even like them for park. Too loose feeling.
He may not ride them now, but he's the reason they exist. He liked the Contact and wanted something beefier: Contact Pro. As evidence: you'll notice the distance between the bottom of the highback and heelcup is greater when folded down on the Pro than any other Union. Ruf found that while bootpacking and holding onto the heelcups the regular highbacks from Union would dig into his hands. So when he got involved with the Contact Pro he had them mill out the bottom section for more hand space.
While it is soft, its not jibby. There's a difference. They're a surfy all mountain binding, a good one. It doesnt sound like he'll be doing "aggressive" freeriding so I dont think he'll out power the Pro's.
Depends what you want and whether you're willing to deal with a toe strap that may or may not fit. The Flux's will fit, the Unions might not. You'll get more dampening from the Union, more response from the TT30, more comfort from the TT30 in my experience, and if it matters to you the Flux's are 100% tool less adjustmets aside from mounting them.
Gdog, have you ridden either the Contacts or Pros? Cause it sounds like you havent. The Contact is one of the softest bindings I've ever been in. They felt too soft on a Sub Zero. The Pros macth up well on rockered mid flex all mountain decks. Far from softer than Contacts. Not to mention they're the same base frame except the Pro's are carbon injected and the Contacts are glass reinforced.