1.
This article has this to say about the decline press:
I cannot believe how this movement is so neglected. The decline Press gives your chest that sharp cut look towards the bottom and is what comple6es the chest separating it from the abs, it rounds out the chest and helps to make it look fuller and gives the chest more thickness than the flat or incline movements can do. As this exercise is primarily used for the lower pectorals it does place a great deal of stress on the middle and upper chest also.
2. I heard that doing cardio prior to eating is better because it gets your metabolism up so the food you eat is immediately burned up and doesn't have to be stored as fat & used later.