Last ‘tips’ I want to share are to frequently stretch out your pecs and front delts. You can probably do these stretches between your rowing sets without them interfering with your workout or outside commitments.
And finally - simply doing all this rowing and pec/delt stretching will not do much in itself to correct your hunched posture (as opposed to your muscle mass imbalance). You need to make a conscious effort in every day life to walk / sit upright with your shoulders pulled back and down (same goes for your head).
I had that hunched look, not from poor exercise selection, but from sitting all day in front of my books (in university) and later my computer (at work) with the shittiest posture imaginable. I figured if I just did more rowing exercises that my posture would magically fix itself. Well it didn’t. It’s not until I forced myself to walk/sit “military style” that it eventually got better.