For a "hotel style turkey breast", I ain't buying into the upside down thing.
The main reason some folks do that with a whole bird is that the legs and thighs take longer to cook than the breast. So to get those parts done, you need to cook the turkey longer, and that dries out the breast. Cooking a whole bird upside down (or doing the multiple turn on it's side thing like I do) exposes the legs and thighs to the hotter part of the oven, and protects the breast.
With a bird that has no legs and thighs, you don't have that worry, so just cook it right side up until the breast is done.
Most hotel style turkey breasts are "enhanced" so they are basically already brined. (Not really, but sort of.) You can still brine it if you like to add additional flavors. My basic turkey or chicken brine is 1/2 cup kosher salt per gallon of water, a can of frozen apple or orange juice concentrate, and then various herbs and spices such as sage, bay leaves, thyme, allspice, sometimes crushed juniper berries.
But for just the breast, you are better off just getting an injector and injecting the breast with a mixture of melted garlic butter, a bit of turkey/chicken stock, and a bit of white wine. Toss in some poultry seasoning to the broth if you like.
Ocean State Job Lot has injectors for about $3 if you do not already have one.........