None of my waistcoats have matching fronts and backs - the backs are almost always silk or some other light material, probably because they're usually worn with a jacket which makes my spine quite warm enough (thank you very kindly!) 
That would perhaps leave you enough to cut the front on the bias which means that the waistcoat would also "mould" itself to me a little more kindly which is useful since the waistcoat is normally worn as a fairly form fitting garment.
I like mine that way, and I often wear a waistcoat because I like them!
Rev'd Father Bill White: Mostly retired Parish Priest & former Elementary Headmaster. Lover of God, dogs, most people, joy, tradition, humour & clarity. Legion Padre, theologian, teacher, philosopher, linguist, encourager of hearts & souls & a firm believer in dignity, decency, & duty. A proud Canadian Sinclair with solid Welsh and other heritage.
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