slowrotor,
I think that you are trying to apply fixed wing theory to rotary wing flight. There is no typical "blade angle of attack" like there might be for fixed wing forward flight. Pitch angle and angle of attack are different in rotary wing (also true for fixed wing - think "alpha"). Angle of attack varies with manouevre, wieght, airflow, blade relative airflow, etc, etc. Use all the groovy formulae given to you earlier, and you will see that you can vary so many of the input values that to talk of a general, or typical value is relatively meaningless in this context.
I repeat my earlier post that there are many different factors affecting blade stall, and angle of attack is but one. To isloate this one factor, or to draw some sort of inference about a particular design based on a single factor in a complex scenario is to miss the whole picture.
I note now that these questions seem to stem from the old R22 report which attempts to indicate that there is some sort of blade stall issue isloated to the R22. You will note that these accident statistics are not replicated in Australia in any way - and they operate perhaps the most demanding of all R22 roles - cattle mustering. This role involves maximum exposure to the possibilities of blade stall: continual ops at max all up weights, extremely high DAs, high manouevre loadings, etc, etc - but there no "blade stall issues" in the accident statistics. No rocket scientist required to figure it out. They are a very statistically reliable aircraft in these neck of the woods.
By the way: a stalled blade does not suddenly fly down and chop through the tailboom. You can research that one on this forum too.
I humbly suggest a commercial pilot level of aerodynamics of RW flight theory may be a good way for you to start if you are at all concerned by the report.