back spacing for a s10

what is a good backspacing for a s10 on air ride laying frame and what is a good size tie for a 18

B/S depends on the width of the wheel. Like 4.5" b/s on an 8" wide wheel or 5" b/s on an 8.5" wheel, etc... I have 18x8 wheels with a 225/40 series tire. I would say its perfect!