one way I figure out angles for tools relative to my work surface is using dial-gauges . pick a machined/ground surface that is parallel or perpendicular with the robot face (if it exists on your tool) and while viewing your current position relative to world or user frame.
you can then jog the robot in tool frame and move it up or down relative to world until you are jogging with the gauge running along the surface you chose on the tool. once you have the tool jogging without moving the gauge, look at your angle values - you should be able to derive