Please help small to big bolt pattern

Wheel backspacing is the measurement from the back of the rim to the mounting flange. Offset is the placement of the mounting flange in relation to the center of the wheel. Basically two different ways to tell you where the mounting flange is in relation to the wheel. Offset is typically more accurate as it takes the bead thickness out of the equation.

To convert back spacing to offset take the rim width plus 1" (because rims are measure inside the beads this adds 1/2" per bead, this is a close approximation), divide by two then subtract the back spacing. A negative answer is positive offset (flange moved to the outside of the wheel) and a positive answer is negative offset (flange moved to the inside of the wheel). So 8" wide rim is 9" overall divided by 2 is 4.5" . If backspacing is 4.5 you have "0mm" offset. If back spacing is 5" you have a positive offset of 1/2" or +12mm or +13mm (yes this is rounded) since its typically represented in mm. If back spacing is 3" then the offset is 1.5" or -38mm and these would look great on a Butt Rockers Camero.