what's the best method for incorporating these? can i just lie on a bench face-down, and horizontally shrug a barbell? is this a good idea?
Use an incline bench instead of flat, and use DB's instead of a barbell.
Are you referring to lat/kelso shrugs? Dumbbells or a barbell may be used.
Bodybuilding is 60% training and 50% diet. Yes that adds up to 110%, because that's what you should be giving it. Change the inside, and the physique will follow.