Overspeeds
Vfr,
Dont know if this is going to be of any help to you because you may already be awear of this, but one way of checking for an over-speed on either the R22 or the R44 is to have a look at the nut that holds the cooling fan in place. There should be a line of white 'torque seal' drawn from on one side of the fan, across the nut and back onto the other side on the fan. If this line on the nut doesnt match up with the two lines on the fan then this may be an indication of an overspeed, allbeit an engine overspeed.
As to checking for brindled bearings in the blades, I dont think there is any way of checking them in a pre-flight, only when the blades come off the A/C.
PA321