My training partner Trog does the over-the-shoulder sweep a ton and has had success with the helicopter. He actually showed me how he's been going the helicopter more without the gi. He's also been hitting the triangle from inverted guard like crazy, which is something I know you're into already.
The variants on that I've been taught emphasize hooking the leg instead of grabbing it...
Originally Posted by Zankou
You may have better success if you get their ankle into the crook of your elbow and turn almost between their legs.
I don't think it'll answer Zakou's question, since he already knows the basics of the sweep, but you can see it taught here (with an alternative armbar at the end).
I notice that when PDP rolls over, he quickly snatches his opponents foot away.
I've only been taught this sweep after failed omoplatas where my opponent postures up and away from me. Will be interesting to try it after watching those two clips (although the music sucked elephantisis afflicted ass).