I calculated an 8-layer case in the Wizard. Then I changed the layer definition to a 7-layer case by just taking one layer out (I set that layer to not used on the left side of the layer definition). But the Wizard still shows the 8-layer case. How can I reset the Wizard, way that it shows the new layer definition?
The Wizard is based on the grids in the model, not the layer definition. Therefore you will need to completely remove the grids for the unwanted layer from the model, then move all the shallower grids up by one layer.
If you have removed e.g. layer 7, you can copy and paste the Time surface from layer 8 into the layer 7 (right-click on the grid > Copy, then right-click > Pasteinto the layer 7 slot). Delete the remaining data from layer 8, close the Wizard window, then then re-run the Wizard for layer 7 using the layer 8 method.
If you have removed e.g. layer 2, it would be probably easier just to rebuild the model without layer 2, since you know which methods you wish to use.