I would perform those movements at least 2x per week.
Your posture will improve, you'll feel it more in your chest when you press. Make sure you are stretching and foam rolling your pecs and pec minors, otherwise you will not get the full effects.
Related articles I wrote:
No, not the very next workout...not likely. But over time, as your shoulders set better and your scap retractors become stronger, you will see improvements. This is something you need to stick with over the course of 3-6 months, not an over night fix.
I started the exercises for the scaps. Hopefully in 3-6 months I will have the sexy meaty chest I have always wanted. I may never leave the house and just have sex with myself.