there's a guy with a series of great videos on youtube. He goes over proper form in great detail, and gives suggestions about what machines, exercises to do. His name is Doug Jones. I think it's called 'best way to exercise'. He suggests using the pullover machine by Nautilus, or probably anything similar. You should have a seatbelt to strap yourself in. This machine puts the weight on your elbows rather than your hands (as a pull-up would). It really nails the lats. I recommend checking out his videos
