Depends on how you do you rodeo 5s. The flatter you get your fives the easier it turns to seven. The more you set it over you shoulder and look for the landing right off the start the flatter they will be
Get a few good fives, and then get a good pop and set the rodeo 5 a bit faster and keep looking.
So not much harder, but if your doing more of a flip then it might be more difficult