How much you need to cut depends on your setup,
i run 285/75/R16 tyres on offset rims with no body lift.
https://www.aulro.com/afvb/images/im...010/03/633.jpg
i have to do it again as the tyre just rubs on the outer corner of the door on full flex and bump stop compression. this would not happen with smaller tyres or if i had a body lift
https://www.aulro.com/afvb/images/im...010/03/634.jpg
https://www.aulro.com/afvb/images/im...010/03/635.jpg
the rear panel shows where i have corrected the cut to stop the rubbing, been too busy to fix the door just yet.
you can see the gap i left between the 2 flares to maximise clearance where dullbirds are flush an much neater.

