decline is great, it is the same exact thing as a dip, your hands are just in a different position and you cant go as deep. my dip bar at the gym is so narrow that i get no chest work all triceps.
the part about the tri's getting worked less is wrong, bad wrong. one of the things about decline is that it takes the should pretty much completely out of the movement and locks it in a static position. thats the reason people decline more than flat ( and also bench more than they incline.) the triceps get hit hard on decline, and thus resembles the dip movement.