Maybe it is because my driveway is flat, but I never have problems with the angles. If I am plowing straight forward, I just float the FEL arms and tilt or curl until the blade just touches the asphalt. If I angle right I do the same thing, then go. Same for angle left.
It is true that if you tilt or curl the blade while it is angled one corner will raise and one corner will fall, but once it is set it is pretty consistent.
Have you tried playing with the spacers for the caster height adjustment? I keep mine with only one spacer above and the rest below the tube for maximum height.