welcome to thr,
I always tell people to try various loads and offerings from the major players in defensive ammo. Ie hornaday, thier tap ammo is very nice, consistent, reliable and accurate, also check remington golden sabers, winchester sxt, winchester ranger, speer gold dots etc. these are some good places to start, personally i would look into the 115 and 124gr+p varietites.
you should get a box of each at least and see that they are reliable, accurate and that you are able to control them shootable to your skill level. which ever one performs the best then i would say go with that. really sd ammo is like buying a gun, you need what works best for you, as well you need what works/ shoots best in your gun.
as far as iwb holsters, check out grandfather oak holsters, they are nice and i have one for my xd sc. there are many other great ones out there, and i am sure that you are gonna get more imput about them form other members. Blad tech is a great place to look as well they make top quality holsters, i have alot of experience with thier products just not thier iwb holsters, but there are many people that have them and carry em.