gears

i had my richmond 3:73s installed yesterday however the backlash was set to 21 thousanths opposed to the recommended 8 thousanths, at slow speeds while turning it makes some nasty noise, does it need to be taken apart again and redone or is she fine for a while, also with the new gear im trying to figure out where to set my shift points

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95 Z28,A4 2:73,3 inch dynomax piping between cat and muffler, flowmaster 80s series,gutted cat,Flowtech Cutout, Moroso CAI, MAF descreened,splash guard removed, hypertech power porgrammer, used for power tuning fan settings and speed limiter