RE: Edge 3D set ups
Actually I have discovered that many of us that were trying to 3D with max throws and a LOT of expo and still weren't getting it had it wrong.
Expo is a great feature on modern radios but too much of it can cause you a lot of problems where you think it's the airplane when it's really the delayed reation to the inputs from the pilot. Cutting way down on expo and learning to fly in 3D rates smoothly makes a HUGE difference in the control of the plane at lower air speeds.
As for doing a harrier roll in low rates.....
Once you know how to do them it really doesn't matter how much roll you input because you can fly a harrier roll through in a slow roll or a faster one, the stick movements and control inputs are the same, the timing of those inputs changes though with the speed of the roll. Attempting to learn harrier rolls with too much aileron can get a beginner in trouble in a hurry because everything is happening too fast for them to keep up with.
The best approach is to find a roll rate that is about one roll per second or a bit faster and practice by starting the roll and holding the stick at the stop while applying rudder and elevator to keep the nose up. Of course as you get the hang of it you might want to pick up the roll rate some more.
It's not hard to do harrier rolls but it does take a lot of practice to make them look good.