The holes are in the centre of the the rail, the first one, outside sill side, to the centre of the hole is 130mm, then from centre of that to the centre of the next one is 325mm, you should be able to mark the rears from that as there is no real point to measure with the curve of the floorpan.... The bolts are captive/ welded in, may be a challenge on the from as there is no access underneath the rail....
Hope that helps, good luck..... Drewdog............
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