how to dish in this area only

[keastab]

I'm working on a little car project and just can not seem to do what I want. I want to dish in the area in the Yellow line on the picture and just in the cone area. basically it is to give a bit more room to the dimmer switch on my car. some of the other cars (same year and make)have the dimmer switch anywhere from 1.5 inches from the wall(mine is too!) to 3 inches from the wall so I'd like to be able to fit this to any style car (same make and model anyway)
any ideas on what I need to do to get the dished in area to follow the curve and blend into the cone?

[Pete Cyr]

Draw your vectors in the area you want the dish and use the dome and subtract function