Heavy Dumbell presses, it's a nice marriage between pushing heavy weight and isolation.
Benches are OK if they work for you and if you don't get rotator cuff injuries.
Mind that the a big bench has to do a lot with strength in lats traps delts and triceps (that's why it can be a great overall upper body power faccillitator), but some people can't get enough pec stimulation due to weak links (delt) or even too strong links (like arms that does most of the work).
dumbell presses flat out work , in one workout TRY:
10-8-6-6 INCLINE
8-6-6-10 FLAT
8-6-6-10 DECLINE
dumbell presses in this order (incline is for most people a weaker biomechanical position, so train inclines first)
As for the flyes, people that have been training for some time can actually build MASS with heavy flyes, but i suggest you become a dumbell press expert first. Shaping is getting lacking parts up to par, maybe you dont even have to shape as your pecs blow up in a favourable shape once the mass kicks in ?
If you want you can use dumbells on chest day, 12 sets, 90 seconds rest inbetween and do a LOW VOLUME strength workout on another that, like 4 * 5 flat benchpress. It needs to be low volume, because you must be recovered before you really hit your chest again with the dumbells. it can be done with a routine that allows 5 days between hitting a muscle again:
day
01 chest (12 sets dumbell presses) - upperback - rear delt
02 front/side delts - biceps - triceps
03 traps - abs (kind ofa rest day, low volume)
04 lowerback - hamstrings - calves
05 BENCHPRESS 4* 5 - quadriceps
06 forearm - wrist - abs (kind ofa rest day, low volume)
The heavy benchpresses are meant to build strength rather than size but there will be a huge carry-over in the sence that it will allow you to push really heavy dumbells for 8 reps and that's when pecs start to raise like bread.