Here is a sketch for a tool that I made to check the roller tracks. You can print it our and cut out the profile. Hold the top edge against the brake spring posts and the line for the "FORNT" or "REAR" is where the track should be.
You may want to use card stock to get a little more stiffness. As stated already, the tracks should be straight without notches. The rear tracks are at a slightly different location than the front, hence the two lines. Many tracks have been repaired over the years with welds to fill in the low spots. These are usable if ground smooth and straight at the correct height.
The Ted's kit allows for the tracks to be at a slightly worn location by using the differing offset of the square head on the kit pins.