I normally don't do olive oil, because it is expensive, but got some pomace olive oil that was on sale the other week, and did a 100% OO batch of HP. I use discounted water (27% water as a % of oils, so it was 270g water to 1000g oil), and a few hours after moulding is was as solid as a rock, the hardest soap I have ever made in only a few hours! It was even getting hard to stamp...
I also had some soap remaining after I filled my first mould, so I beat it with the egg beater, and moulded it. That soap was even harder, very nice to cut, very clean edges as well and the surface was a lot less tacky and more dry feeling. It looked about the same as the non-whipped, but it floated. The whipping probably facilitated even more evaporation.
I think reducing the water might be worth a try to get harder OO.