Tom;
Sorry I didn't answer your post, I haven't been on the site in a few days.
Rich Stern is dead on, great, truthful answers. I agree with Rich 100%, and IMO you are making the right choice for you. Well informed, smart. And yes, CT Laser grips from S&W are typically less expensive when you buy them with the gun. If you practice with & without the laser, you'll become very comfortable. Remember to keep a check on the battery (inside the grip).
I am very happy that you found some of my information useful, and that we can agree.
I've had the same gun shop experiences, and I'm very well versed and knowledgeable regarding ballistics and firearms. That's where the maturity comes in, the guy with the "my gun is bigger than yours" subscribes to the Peter Principle. You may read about him in the news someday. You did the right thing by walking away and finding a responsible shop.
And kudos to you for eye and ear protection.
Please keep in mind for the future, with your S&W, use only factory loaded ammo, unless you personally become very knowledgeable on reloading ballistics. An exception, with your detailed knowledge and understanding, may be your "friendly" gun shop owner if they sell reloads.
Good Luck!