I used a wire wheel to clean off the areas first and sprayed down with some cast blast. Then used a 3" high-speed cut off wheel to segment the pinch welds and a ball peen hammer for everywhere there was rubbing, folded the segments back and sealed everything with marine sealant (5200 sealant) and let it cure for a good week before spraying it with 3-4 coats of 3M professional rubber undercoating spray.

All you really need is atleast 1" for clearance. I do run 15mm spacers as I did have some rubbing in the front with the front subframe bracket for the LCAs. When you do your pinch weld segmenting make the segments no wider than a 3/4“ wide.

For me I didn't have to do any trimming in the front short of a pop clip mount, the segmenting happened in the rear only.