Like Kalle said, you have to get the stone on your chest and explode up.
The other tip that I was told for stone loading in general is that you want to be a crane, not a forklift. Once I have the stone lapped I re-adjust my arms. Instead of hugging it you want to reach over the top. If the stones on your chest and not your belly this allows you to get it much higher.
@0:40 you can see what I mean, high on the chest and reach over
And then you have Kevin Knee using the forklift technique