Congrats on the new addition. I also have a Glock gen3 G23 and it is my primary. I've been carrying it ever since I received my CCDW. I think you'll find that your Glock is going to eat just about anything you throw at it. Mine runs no matter what I put in it. For practice, buy whatever is the cheapest thing you can get your hands on. If for whatever reason, you find your gun won't run on what you're feeding it then switch over to something that will work. I don't think that will happen but in the unlikely event it does, you'll have it covered.
I would try to practice with a weight similar to what you plan on carrying. I'm told it won't make much difference but I like to stay the same if I can, etc.
Do some research on SD ammo and make your decision accordingly. Find out what works on the streets, read reports made from LEO experiences, etc. Ask around (like you have done here).
I think you'll find that there's a lot of good ammo out and you'll do well by using something like Ranger Ts, Federal HST, Remington Gold Sabre and Speer Gold Dots. Personally, I carry Gold Dots in 180gr. but 165 gr. is also a good choice.
I hope this helps and the best of hope goes out to you!
DCG