Press/push presses off a Power Rack/A frame/squat stand, etc can give the greatest potential for front delt mass. Worth the time invested. Middle to close grip. A wider grip can cause shoulder joint problems for quite a few trainer's. The bench press will also improve from just the press/push presses.
Front raises, though a good exercise, is not a great exercise for adding pure muscle mass. Front raises are an extension/leverage movement and limit the weight used. I have seen guy's use the BB front raise while lying on a incline bench, for a shorter ROM. This takes the stress off the lower back that may occur with the regular standing version. And more weight seems to be handled. With DB lying incline front raises, a greater ROM (and stretch) is given. And again, less stress on the lower back. Good Luck.