What exactly is the difference? You can build mass. Definition is a product of genitics and low body fat. It has been popular for the pros to write about heavy load workouts while bulking and then switch to lower weight high rep routines while dieting down. The reason is obvious. Cut calories and reduce energy levels....Work towards building a large chest. The rest will come naturally.
1. heavy mass builder = flat bb bench.
2. heavy stretching movement = db pullovers
3. low incline db press
4. pec deck to finish them off.