The guillotine press – where you bring the bar down to your neck instead of the lower pecs – is a great chest developer. But there is risk. Keep these light and under control. This is not a bench press variation to go heavy on. And don't try to set a PR! This is bodybuilding, not powerlifting.
My favorite way to use it is 6 x 6 with 20 second rest periods between sets.
There are plenty of ways to ratchet up the intensity of a set, like forced reps, Tom Platz iso-holds, and rest/pause sets, but you need to apply them in two-week waves.
Didn't it seem that the bodybuilders of yesteryear had bigger chests? (We're talking chest circumference here and not pec size, mind you.) Ellington thinks so and he knows why - it was all due to the all-but-lost art of ribcage expansion.