Cooking a Turkey crown
The idea of cooking a turkey upside down is that the fat from the fattier bits of the bird (the legs etc) runs down into the breast. As a crown has none of these bits, there's no point in cooking it upside down.

By all means butter and bacon it though - turkey breast is very lean so needs all the fat it can get to keep it moist, so use good fatty bacon.

Take it out of the fridge a good hour before you cook it, preheat the oven to 180C, and cook for 20 mins per pound (454g) + 20 mins. Baste regularly, but be aware that every time you open the oven door the heat drops dramatically, so don't be overzealous - once every 20 minutes should be ok. Then let it rest for half an hour, on a warm plate, under foil. This will help with juiciness.