Tilted up arms are for aircraft that have crappy flight controllers where you are happy to be able to just hover in perfect weather. (I won’t tell you how I really feel 
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Yes this is correct. It helps the aircraft quickly take up the additional constant loads.
If possible yes. There is absolutely nothing good about tilted up arms/propeller disks, so there is never an excuse for that.
Soft propellers blades reduce the shock loads on the airframe and motor in particular so this is a trade off.
I generally do both but if the aircraft autotunes well then that makes things easy.