13 x 13 and 9 x 9 tournaments: how would auto handicap work for large rank differences?

As part of an ongoing series of online Go classes I would like to offer handicap tournaments where both teachers and students could participate with appropriate handicap settings.

Is there a handicap table available that would show what the handicaps would be for a range of rank differences?

Where would the handicap stones be placed?

In particular I’m interested in what the handicaps would be for differences of 13-19 ranks.