Back spacing

[ibinyth]

Looking to possibly run rocket racing attack titanium wheels. It's a 70 c10 4/6 drop wheels will be 18"

Not sure if I can run a 10" up front or not, front is stock arms, here are the options for back spacing... I do own a angle grinder if need be

Front
18x10 5", 5.5"
18x9 4.5", 5"
Rear (no tubs or bed floor) I believe I have the later rear end, I remember my axle shafts were 31.313", I don't have the rear end with me, it's being rebuilt.
18x12 6", 5.5"