I have both but only the BlackGold has fruited for me. Both cherries are self fertile. They are both quite hardy for sweet cherries. My advice would be to buy both on a dwarf or semi-dwarf rootstock and see how they work out for you since time is very expensive and you can’t buy more of it. On dwarfing rootstock you can keep the trees in a small space and have a tree that is easy to care for.
BlackGold flowers very late and it’s bloom overlaps with my Montmorency tart cherry. It is susceptible to canker but many people on the forum have been successful in spite of this problem. I think if you would limit yourself to pruning only in the Summer your risk of having a problem with canker would be greatly diminished. Fruit set and yields are higher than on WhiteGold.
WhiteGold blooms earlier than BlackGold and that makes it a better pollinator for most cherries. BlackGold will escape late frosts but blooms too late to pollinate many sweet cherries reliably. See this bloom and pollen compatibility chart.