I have a new client who says the previous owner who operated the wood/oil furnace for +40 years suggested the new owners should order their wood to be 19" long with a 9" split. Now 19" is the easy part, I've never heard of the 9" split phrase. Does that mean no wider than 9" width? The new owner said the firebox is huge, 30" deep and over 12x12" door opening.