yes, there are mating surfaces. Mating surfaces and ejector pin mark places. I intended to specify the largest mating surface as datum A plane. Datum B and C will then be 88 deg with respect to A.
Usually we pick surfaces that are mutually perpendicular to each other as datum planes. What's the best practice to pick datum planes if all of the surfaces of the part is drafted and there are no surfaces perpendicular to each other ?
