need help with a drop

[fpjr0]

HI I am droping my truck I think I am going for a 6/7 I know the kits are normally 5/7 but here a explanation on why , see if you guys can help.....
ok.... I measured from the edge of the fender my drive way floor , they are as folllow 31 1/4 front driver 31 5/8 front pass side 32 1/8 rear driver and 31 1/2 rear pass, I am running 15x8 rally's with a 275/60r15 set up , which i think is a 26 inch tire or so... I am wanting to do a static drop(slam) with some 20x8.5 in front and 20x10 in the rear, dont know the exact tire size yet but I am thinking its going to be around the 29 inch area, right now the gap between the edge of the fender and the top of the tire is around 5.inches this is only the first truck i ever drop. so i am a little lost, I am thinking whe I do the 29ish tire, the gap between the tire and fender edge should be cut to around 3 1/2 from the taller tire, and the overall high of the truck become around 1.5 inches higher, but might be over thinking it... I just feel lost, and the trucks height is ever front/rear since my front came up after I swaped the 5.3/4l60e combo.. any help pls.., but have no idea about what kit to buy....the pic might look a little funny from making it smaller