Hit the lower chest hard.
Keep the dumbbells tracking over your lower chest, not drifting toward your face.
The decline angle lines the pressing path up with the lower chest fibres and shortens the range slightly, which is why most lifters are strongest pressing on a decline. Dumbbells add a stability demand a machine or bar never asks for, each side must control its own path, with the triceps assisting through the press. It earns its place for building the lower chest and for lifters whose shoulders grumble on flat pressing, since the decline keeps the upper arms in a friendlier position.
For many lifters, yes. The decline keeps the upper arms lower relative to the torso, which reduces the shoulder stress some people feel on flat and incline pressing. If flat bench bugs your shoulders, it is worth a run.
Stopping just shy of full lockout keeps tension on the chest instead of letting the arms stack and rest at the top. You lose nothing on growth and keep the muscle working for the entire set.
Straight up over your lower chest. Because your head is below your hips, there is a natural pull to let the weights drift toward your face, fight it and keep every rep stacked over the lower pecs.
