Has he actually ever gone for a double legż Jones Greco-awesomeness might have clouded my memory, but I can't remember any double leg, only a ton of TDs from the Greco clinch.
The Machida takedown was a double. Jones didn't drive through him the way Sonnen does, but he basically got a hold of his legs and then pulled them upwards.
As for the height/reach advantage, Gus had better plan on setting up his power hand. If he hopes to pepper Jones with Jabs he's going to come up short simply because Jones is better at it.