I think i got about 5 on my 2" rear drop on the H&R sports, and my rear tires wear perfectly. I went all spring and summer without any abnormal wear on the rears. My alignment spec sheet that was given to me verified my specs. I personally would not put 7 washers on. If you need that much camber correction, then purchase some Ingalls rear camber kits, as those are made to correct safely for that much negative camber.