The Reno Rockers are one thing, because they have minimal rocker (compared to the Hellbent) and they are on 90mm in the waist. They will be a good park ski, especially if they can hold an edge like they claim. That being said, they still won't pop like a regular park ski. It's physically impossible, they don't have camber. Also, you will wash out more on back seat landings, there is no avoiding that (I'm probably one of the few guys here who has ridden rockered skis for an entire season).  It will be a wicked ski to butter, but only when buttering will you be able to pop at all.
Hellbents are not a park ski. They have ridiculously huge rocker and are fucking fat and thus quite heavy. Keep in mind that when Pep and Andy are in the park (not pow and backcountry, thats a completely different story) they are using rockered Made'ns. 108 waist vs. 122. That ski is going to be a lot lighter. Also, did you see them in the X-games? They couldn't carry speed worth shit and were washing out like crazy on anything they landed backseat. Pure and simple if you buy Hellbents, you have to have another pair of skis. I'm sure they're wicked in pow and trees and booters and all of that, but you're going to be extremely disappointed with their performance in the park. Too fat, too heavy and too much rocker.
If you want a little rocker, buy the Reno Rocker or the Seth. Or just buy a soft park-specific ski.