A couple fun things to address here:
1) you've already started a thread on this exact topic. I assume you didn't like the advice you were getting there so you started another one. In your defense, you have included more information and questions here, so it's KINDA new, but that's generally not really good practice. Kinda like going to Mom to ask if you can go out and play because Dad said no.
2) you seem stuck on a few constructs that you absolutely must have: you are insistent that you must do flat, incline, and decline, but in your prior thread when someone asked about including all 3 in the same workout, you worried that was too much volume. Which brings us to another key point:
No one can give you good advice about how to train one specific body part withot knowing what your whole training week looks like.
Asking for advice on how to train chest without knowing whether you do a body part split, an upper/lower, a push/pull/legs, a full body routine...the answer for "how to train chest" - the way you're asking the question, demanding a specific number of sets, reps, and weights on certain days of the week - requires this knowledge,
If you do a bodypart split, it is perfectly reasonable to suggest that your chest day be entirely comprised of flat, incline, and decline DB presses. 4-5 sets of each seems like it would make a fine chest day.
If you do upper/lower or full body, that might be a little much for one workout and you may want to split them up.
See where this is going? We can't tell you "how to train chest" in a vacuum.
3) strength and hypertrophy are not mutually exclusive things. When you say you want the one set-and-rep scheme that will retain strength but allow room for hypertrophy...I mean, just think about how dumb that sounds. You expect that doing 4x11 will make your muscles grow but allow you to get weaker? Huh?
It's been said many times on this site: train in a variety of rep ranges. Thibadeau posted an article the other day with, like, 22 rep schemes. Go read that article. Pick the ones you like best. Rotate through them every couple of weeks. You don't have to do 3x8 EVERY SINGLE WEEK.
Final Thought: I'm inferring from your post that you want someone to lay it all out for you, give you THE ONE TRUE ANSWER: "I have run my algorithms and concluded that you should do 3x8 with 60 pounds for incline, 65 for flat, and 70 for decline. That will be 20 dollars. Thanks and have a nice day."
The problem is that IT'S NOT THAT SIMPLE. Rather than asking for that ONE TRUE CHEST WORKOUT, I suggest that you consider the basic principles of training, your primary goals, your OVERALL weekly setup, and learn to adjust. Some days you might go heavier. Some days you might go lighter, for higher reps. THERE IS NO ONE ANSWER. People have gotten bigger, stronger, leaner with dozens and dozens of different programs. So instead of worrying about whether you are doing the right permutation of sets, reps, and assorted dumbbell presses, how about this: do a handful of sets of DB press (flat, incline, decline) every time you are working "chest" - pick a modest weight (40 pounds?) and do 10 reps. Put them back, rest a minute, pick up the next set of DB's and do 10 reps. Repeat until you can no longer get 6 reps. You'll get a blend of volume with the first few high rep sets and "strength" work as the weight creeps up.