when i shaved mine on my 96 ford i used a sawzall while standing on the bed and proceded to slice throught he double metal. once the majority of it was cut off i took the and grinder to gently take off whatever metal off to smooth it out. then i tacked the roof skin to the inner lip of the cab seam. after all that was done i smoothed the weld with the grinder. i then took a piece of 3/16 solid round rod and then weled that in place to give it some more stuructural intergrity. when that was all welding it place and smoothed out. (which makes it stronger and uses less filler) once that was done i took some masking tape and taped off the top part of the door (leaving the wheather strip on and all) once everthing was taped off i shut the door. then took kitty hair and filled in the gap. once it was almost cured i opend the door up and used the cheese grater to get the general shape. after that was done i put a light layer of quality bondo over it. once all the sanding was done i had a gaps perfect. it took a good solid 2 days of working on it strait. take your time and dont ward the roof. its very thin metal. hope this helps.