In most cases this is a simple mathematical problem. Given the pattern instructions I would expect the distance from the vest shoulder to bottom of the front to be no more than 27" (3/4 of a yard) otherwise you would need more fabric for cutting on the straight grain. So, as long as you have at least twice that (54") width of fabric then the front panels can be rotated anything up to 180 degrees and still fit on the fabric (and you will only need to rotate about 40-45 degrees)

Without seeing the pattern it is impossible for me to say whether you need extra fabric for pocket flaps or collars etc but you should, at the very least, get two basic vest fronts cut out on the bias and that is really all you need. The lining and the backs (outer and lining) can all be made in satin lining fabric and even if there's not enough tartan for pocket flaps there should be plenty enough left over for simple welt pockets