With such low miles on the engine using an above average amount of
oil would not be a big suprise but one quart per 300 miles is way out of line. I would suspect a valve stem seal has popped loose or didn't get installed correctly to begin with. There are methods of using compressed air in the spark plug hole to secure the valve so you can use a spring tool to remove it for seal inspection & replacement. If not addressed soon you risk the danger of badly carboning up the rings in the offending cylinder. This would mean major dissasembly. If you paid someone else to build this engine it should be a warrantable issue. Other far worse possibilities could be but not limmited to an
oil galley leaking past the head gasket, lined up ring end gap or broken rings. If you have access to a bore scope you could take a peek in the offending cylinder with the intake valve open & inspect the valve & cylinder walls for clues.
Gorgeous car by the way!!!!!!
Matt