I want to put on maybe 5 or 10 pounds of muscle. If I bought 2 dumbells with adjustable weights, would I be able to target most major muscle groups effectively to increase mass? We have a machine in my house, but my understanding is that machines are usually less effective for functional strength than free weights. Would there be many/any muscles that the dumbells will not be able to help me target? I would go to a gym, but among martial arts, school, and other things, it would be much more convenient if I could lift at home. Any other pointers? Thanks.