any amount of throttle wants to make the plane climb. As described above, the wing is stalled and the plane is hanging on the prop. This sounds like you need a fair amount of throttle to do a harrier, correct? Next time out, I will try the wall, hover entrance into a harrier.
If you watch any experienced 3d pilot's, they never keep the throttle in one spot. You need to learn to "pump" the throttle. Each little gust of wind will help to correct the position of the plane. Also, most planes have a different angle that it likes to hover.
3D flying takes a lot of time to learn proficiently....Remember back to when you were learning to turn when the plane was flying directly towards you, or when you learned to fly inverted. I'm sure now, you dont even have to think about which surface to move
After a while, you will get "muscle memory" and you will stop having to focus so hard on which corrections you have to make.
I also agree (although it's a bad habit to get into) that spoilerons do help when learning to hover.