I sadly don’t know too much about TIR’s, and perfer reflectors. There was a topic posted disscussing if TIR or reflectors were best, and most perfered TIRs then. From what I know, the angle and surface of the TIR should mostly just affect the concentration and throw, not really the beam pattern in any other way.
Here is a picture I found. It is not really the best, but it helps to some degree.
