help with a bridge..

my friend wants my help with putting his suicidedoors bridge on his isuzu, its the 8" notch.. i know we could just weld the notch on there to lay on big ass wheels, and build taller lower bag brackets to not lose any lift.. but right now he has 17" escalades with 40 series tires, and he said thats the biggest hes getting. now i know how to measure frame to ground, axle to frame to find out how high the actual notch should be, but with it at that height will the bag bracket spacing be right or do you go by the bag bracket spacing and let the notch be however high it ends up when the bags fully compressed?