For quick and accurate marking of dovetails, a guide is the best way to go. The Veritas Dovetail Markers are designed to be large enough to cater for most sized dovetails, and able to flipped over to allow both slopes of the dovetail to be marked.
Their design allows the front face of the dovetail to be referenced from the top mark, eliminating any guess work.
Made from aluminium, they are light and will not damage the timber.
The 14° angle is traditionally used in blind dovetails, when making drawers, so the joints are hidden from the front.