...and sometimes i used it to monitor isn't my engine in lean or rich condition.
With 3/4 stick hover you can also monitor if your engine is lean or rich, I don't understand this point??
i think one of the reasons for having a 1/2 stick hover is so that you can have 2 pitch settings after the hover point.. with 3/4 stick, you only have one.
That depends on the number of points in your pitch curve. Anyway the curve should be linear so any number of points will work.