I think a brine would be a must on a skinless chicken breast, unless you want a dry one. It's amazing what a good brine will do for certain meats! Time?....depends on the size, of course, but you want an internal of 165.
Inject them. Once injected (and you have to do this slowly), coat with oil, butter whatever and bacon. They won't take but about 2 hours at 250 to get up to temp and be still juicy.